-
a
aindefinite articlenot any particular or certain one of a class or group.
-
A
Anounthe first letter of the English alphabet, a vowel.
-
Å
Åangstrom.
-
a'
a'adjectiveall.
-
a-
a-a reduced form of the Old English preposition on, meaning “on,” “in,” “into,” “to,” “toward,” preserved before a noun in a prepositional phrase, forming a predicate adjective or an adverbial element (afoot; abed; ashore; aside; away ), or before an adjective (afar; aloud; alow ), as a moribund prefix with a verb (acknowledge ), and in archaic and dialectal use before a present participle in -ing (set the bells aringing ); and added to a verb stem with the force of a present participle (ablaze; agape; aglow; astride; and originally,awry ).
-
-a
-aa plural ending of nouns borrowed from Greek and Latin.
-
A-
A-atomic (used in combination).
-
a.
a.abbreviationyear.
-
A.
A.abbreviationyear.
-
a–
a–A prefix meaning “without” or “not” when forming an adjective (such as amorphous, without form, or atypical, not typical), and “absence of” when forming a noun (such as arrhythmia, absence of rhythm). Before a vowel or h it becomes an– (as in anhydrous, anoxia).
a
1 Americanindefinite article
-
not any particular or certain one of a class or group.
a man; a chemical; a house.
-
a certain; a particular.
one at a time; two of a kind; A Miss Johnson called.
-
another; one typically resembling.
a Cicero in eloquence; a Jonah.
-
one (used before plural nouns that are preceded by a quantifier singular in form): a hundred men (comparehundreds of men ); a dozen times (comparedozens of times ).
-
indefinitely or nonspecifically (used with adjectives expressing number).
a great many years; a few stars.
-
one (used before a noun expressing quantity).
a yard of ribbon; a score of times.
-
any; a single.
not a one.
preposition
preposition
auxiliary verb
abbreviation
noun
-
A's,
plural
-
As,
plural
-
a's,
plural
-
as
plural
-
the first letter of the English alphabet, a vowel.
-
any spoken sound represented by the letter A or a, as in bake, hat, father, or small.
-
something having the shape of an A .
-
a written or printed representation of the letter A or a.
-
a device, as a printer's type, for reproducing the letter A or a.
idioms
-
not know from A to B, to know nothing; be ignorant.
-
from A to Z, from beginning to end; thoroughly; completely.
He knows the Bible from A to Z.
-
the first in order or in a series.
-
Sometimes a
-
(in some grading systems) a grade or mark, as in school or college, indicating the quality of a student's work as excellent or superior.
-
(in some school systems) a symbol designating the first semester of a school year.
-
-
Music.
-
the sixth tone in the scale of C major or the first tone in the relative minor scale, A minor.
-
a string, key, or pipe tuned to this tone.
-
a written or printed note representing this tone.
-
(in the fixed system of solmization) the sixth tone of the scale of C major, called la.
-
the tonality having A as the tonic note.
-
-
Physiology. a major blood group, usually enabling a person whose blood is of this type to donate blood to persons of group A or AB and to receive blood from persons of O or A.
-
Sometimes a the medieval Roman numeral for 50 or 500.
-
Chemistry. (formerly) argon.
-
Chemistry, Physics. mass number.
-
Biochemistry.
-
Logic. Also a universal affirmative.
-
British. a designation for a motion picture recommended as suitable for adults.
-
a proportional shoe width size, narrower than B and wider than AA.
-
a proportional brassiere cup size, smaller than B and larger than AA.
-
a quality rating for a corporate or municipal bond, lower than AA and higher than BBB.
adjective
abbreviation
abbreviation
abbreviation
-
about.
-
acre; acres.
-
active.
-
adjective.
-
alto.
-
ampere; amperes.
-
anonymous.
-
answer.
-
are; ares.
-
Baseball. assist; assists.
abbreviation
abbreviation
abbreviation
-
Absolute.
-
Academy.
-
acre; acres.
-
America.
-
American.
-
angstrom.
-
answer.
-
April.
-
Artillery.
symbol
-
music
-
a note having a frequency of 440 hertz ( A above middle C ) or this value multiplied or divided by any power of 2; the sixth note of the scale of C major
-
a key, string, or pipe producing this note
-
the major or minor key having this note as its tonic
-
-
a human blood type of the ABO group, containing the A antigen
-
(in Britain) a major arterial road
the A3 runs from London to Portsmouth
-
-
a film certified for viewing by anyone, but which contains material that some parents may not wish their children to see
-
( as modifier )
an A film
-
-
mass number
-
the number 10 in hexadecimal notation
-
cards ace
-
chem argon (now superseded by Ar )
-
ampere(s)
-
Also: at. ampere-turn
-
absolute (temperature)
-
(in circuit diagrams) ammeter
-
area
-
(in combination) atomic
an A-bomb
an A-plant
-
chem affinity
-
biochem adenine
-
logic a universal affirmative categorical proposition, such as all men are mortal: often symbolized as SaP Compare E I 2 O 1
-
-
a person whose job is in top management, or who holds a senior administrative or professional position
-
( as modifier ) See also occupation groupings
an A worker
-
abbreviation
determiner
-
used preceding a singular countable noun, if the noun is not previously specified or known
a dog
a terrible disappointment
-
used preceding a proper noun to indicate that a person or thing has some of the qualities of the one named
a Romeo
a Shylock
-
used preceding a noun or determiner of quantity
a cupful
a dozen eggs
a great many
to read a lot
-
used preceding a noun indicating a concrete or abstract thing capable of being divided
half a loaf
a quarter of a minute
-
each or every; per
once a day
fifty pence a pound
-
a certain; one
to change policy at a stroke
a Mr Jones called
-
(preceded by not) any at all
not a hope
symbol
-
acceleration
-
are(s) (metric measure of land)
-
atto-
-
chess See algebraic notation
noun
-
the first letter and first vowel of the modern English alphabet
-
any of several speech sounds represented by this letter, in English as in take, bag, calm, shortage, or cobra
-
Also called: alpha. the first in a series, esp the highest grade or mark, as in an examination
-
from start to finish, thoroughly and in detail
abbreviation
-
acre(s) or acreage
-
America(n)
-
answer
prefix
-
on; in; towards
afoot
abed
aground
aback
-
literary (used before a present participle) in the act or process of
come a-running
go a-hunting
-
in the condition or state of
afloat
alive
asleep
symbol
prefix
verb
preposition
determiner
Grammar
In both spoken and written English the choice of a1 or an 1 is determined by the initial sound of the word that follows. Before a consonant sound, a is used; before a vowel sound, an : a book, a rose; an apple, an opera. Problems arise occasionally when the following word begins with a vowel letter but actually starts with a consonant sound, or vice versa. Some words beginning with the vowel letter u and all words beginning with the vowel letters eu are pronounced with a beginning consonant sound, as if the first letter were y : a union; a European. Some other spellings that begin with a vowel letter may also stand for an initial consonant sound: a ewe; a ewer. The words one and once and all compounds of which they are the first element begin with a w sound: a one-room apartment; a once-famous actor. The names of the consonant letters f, h, l, m, n, r, s, and x are pronounced with a beginning vowel sound. When these letters are used as words or to form words, they are preceded by an : to rent an L-shaped studio; to fly an SST. The names of the vowel letter u and the semivowel letters w and y are pronounced with a beginning consonant sound. When used as words, they are preceded by a : a U-turn; The plumber installed a Y in the line. In some words beginning with the letter h, the h is not pronounced; the words actually begin with a vowel sound: an hour; an honor. When the h is strongly pronounced, as in a stressed syllable at the beginning of a word, it is preceded by a : a history of the Sioux; a hero sandwich. (In former times an was used before strongly pronounced h in a stressed first syllable: an hundred. ) Such adjectives as historic, historical, heroic, and habitual, which begin with an unstressed syllable and often with a silent or weakly pronounced h, are commonly preceded by an, especially in British English. But the use of a rather than an is widespread in both speech and writing: a historical novel; a habitual criminal. Hotel and unique are occasionally preceded by an, but this use is increasingly old-fashioned. Although in some dialects an has yielded to a in all cases, edited writing reflects usage as described above.
Other Word Forms
Noun Inflected Forms
Etymology
Origin of a1
First recorded in 1200–50; Middle English; originally preconsonantal phonetic variant of an 1
Origin of a2
Originally Middle English a, preconsonantal variant of on ( a- 1 ); confused with a 1
Origin of a3
Middle English; unstressed preconsonantal variant of of 1
Origin of a4
First recorded in 1300–50; Middle English; a phonetic variant of have
Origin of a5
First recorded in 1200–50; Middle English a, ha
Origin of a-12
Middle English, late Old English; cf. a 2, nowadays
Origin of a-13
Middle English; see a 3
Origin of a-14
Middle English; Old English a- (unstressed), ǣ-, ā-, ō- (stressed; see abb, woof 1, oakum), rarely or- ( see ordeal), ultimately from unattested Germanic uz- from unstressed Indo-European uss-, from ud-s (these latter two also unattested), akin to out; in some cases confused with a- 4, as in abridge
Origin of a-15
Middle English < Latin ā-, a- (variant of ab- ab- ); in some words < French a- < Latin ab-, as in abridge
Origin of a-16
Middle English, in some words < Middle French a- < Latin ad- prefix or ad preposition ( ad- ), as in abut; in others < Latin a- (variant of ad- ad- ), as in ascend
Origin of -a20
From Latin feminine ending -a, as Claudia, feminine of Claudius; see -a 2
Origin of -a21
Probably generalized from the -a of magnesia
Origin of a.23
< Latin annō, ablative of annus
Origin of a.24
From the Latin word ante
Origin of A.26
< Latin annō, ablative of annus
Origin of A.27
From the Latin word ante
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Turing has established a joint research partnership on autonomous driving with carmaker Subaru and auto-parts supplier Denso, both of which have a presence in the U.S. and other overseas markets.
From The Wall Street Journal ● Aug. 12, 2026
“It’s feeling a lot better right now. So that’s encouraging.”
From Los Angeles Times ● Aug. 12, 2026
“We do have a second-mover advantage,” Yamamoto said, adding that Turing is about three years behind Tesla in autonomous-driving technology and less than a year behind British startup Wayve.
From The Wall Street Journal ● Aug. 12, 2026
“And so it puts my arm in just a fine spot, and obviously, we just worry about the muscle.”
From Los Angeles Times ● Aug. 12, 2026
By now, she says, the horrors of World War II “stand out in a kaleidoscopic pattern in my memory.”
From "At Last She Stood" by Erin Entrada Kelly
![]()
A true AI assistant, like the one in the movie “Her,” is the holy grail of the technological race afoot.
From The Wall Street Journal ● Aug. 12, 2026
A complete list of the recalled items that includes a UPC code can be found here.
From Los Angeles Times ● Aug. 11, 2026
A young woman whom Bornali had never met, helped with food, cleaning and looking after her 60 surviving goats.
From BBC ● Aug. 11, 2026
A proposed class-action suit was filed in federal court in Manhattan alleging that StubHub sold hundreds of World Cup resale tickets it was neither authorized nor able to deliver.
From The Wall Street Journal ● Aug. 11, 2026
A stray cloth, a spoon, a rag doll, and a pink ribbon are scattered, forgotten.
From "Will’s Race for Home" by Jewell Parker Rhodes
![]()
In the new study, the research team employed state-of-the-art cryo-electron microscopy techniques to capture nine different states associated with the lipid transport and determine structures at 2.4 to 3.1 Å resolution for these states.
From Science Daily ● Dec. 5, 2023
Danish, an often staccato language spoken by only about six million people and whose alphabet includes the letters Æ, Ø and Å, is perhaps an unlikely choice for pop’s next lingua franca.
From New York Times ● Apr. 19, 2023
Note: The length unit angstrom, Å, is often used to represent atomic-scale dimensions and is equivalent to 10−10 m.
From Textbooks ● Feb. 14, 2019
Ten days after discovery, the dominant feature in the spectrum is a broad emission centred at about 21,000 Å.
From Nature ● Oct. 15, 2017
At the third epoch, when near-infrared wavelength information was again available, the peak shifted further to 11,000 Å and the overall spectral shape changed.
From Nature ● Oct. 15, 2017
Some songs—such as “A Guid New Year to ane a’ A’”—were widely recognized.
From National Geographic ● Dec. 27, 2023
The Scottish government agreed with a recommendation by Sepa which allows Scottish Water to increase abstraction levels from the Allt a' Mhuilinn burn.
From BBC ● Jun. 17, 2023
Whether all this adds up to some big change a’ coming to City Hall, it’s too soon to say.
From Seattle Times ● May 24, 2023
After a’ dominating Thanksgiving win over Dallas two-plus years ago, Anthony posted a clip of his brother’s leaping pick-six of quarterback Andy Dalton and urged people to vote for Sweat to make the Pro Bowl.
From Washington Times ● Jan. 5, 2023
“Oh lord, Sierra, really? Everybody has a little gut, and plenty a’ dudes go crazy for ’em.
From "Shadowshaper" by Daniel José Older
![]()
Important, too, was the morpheme a-, which referred to the mouth and, more broadly, to origins.
From Scientific American ● Jun. 14, 2023
That giant thing of spices that looks like a-
From Salon ● Mar. 30, 2019
Average sizes are about 2.0 μm and 1.2 μm along the a- and c-axes, respectively. b, AFM height image and height profiles for the MFI nanosheets.
From Nature ● Mar. 14, 2017
The Israeli grandmaster plays the positional side of a Benko Gambit to perfection, building up great pressure on the a- and b-files while the great Benko bishop strafes the White position from g7.
From Washington Times ● May 12, 2015
"Well, don't do it again. Understand? Not at night There's enough silly talk about beasts, without the litthlus seeing you gliding about like a-" The derisive laughter that rose had fear in it and condemnation.
From "Lord of the Flies" by William Golding
![]()
I don't think the "-e" should eliminate the existing "-o" and the "-a."
From Salon ● Sep. 26, 2022
During the scenes, partly I'd be thinking what an incredible job the set dressers had done, but there were shocking moments -a scene in Highgate cemetery with Nazi soldiers chilled me inside.
From BBC ● Feb. 20, 2017
He needs to grow up or get out -a cancer in the locker room.
From New York Times ● Jan. 9, 2017
Hanks' character -a boy in an adult body - ends up working for a toy company headed by Loggia.
From Reuters ● Dec. 4, 2015
Lady Donella Homwood brought no tail of knights and retainers,- only herself, and six tired men-at-arms with -a moosehead badge on their dusty orange livery.
From "A Clash of Kings" by George R.R. Martin
![]()
"The All Blacks are a classy outfit, and they'll punish you if you're not on your A- game, and at times we weren't," admitted Irish skipper Dan Sheehan.
From BBC ● Jul. 18, 2026
Yet the average high-school math GPA was an A- for students taking a middle-school remedial course.
From The Wall Street Journal ● Nov. 24, 2025
“Frozen Empire” garnered a B+ CinemaScore from moviegoers, a tick down from the A- score for “Afterlife.”
From Seattle Times ● Mar. 24, 2024
A recent report card from Children Now, a nonprofit advocacy group, rated California a D on children’s access to preventive care, despite the state’s A- grade for ensuring children have coverage.
From Los Angeles Times ● Feb. 26, 2024
In 1926 it was decided to build A- and B-blocks on the hill, and in 1929 they were completed, along with the chapel and mess hall.
From "Newjack: Guarding Sing Sing" by Ted Conover
![]()
This makes sense as 1 = loga a means a1 = a. which is true for any a.
From Textbooks ● May 6, 2020
Use your answers to parts a. and d. to determine which of the three options is best.
From Textbooks ● Mar. 30, 2016
Find the derivative of the equation in a. and explain its physical meaning.
From Textbooks ● Mar. 30, 2016
Use the answer to part a. to find a general formula for the present value of payments of C dollars received each year over the next n years, assuming an average annual interest rate r.
From Textbooks ● Mar. 30, 2016
He stops abruptly, almost dropping me, as he reaches a. wide hallway with panes of glass on either side, revealing offices.
From "Insurgent" by Veronica Roth
![]()
“The message to everyone in the police department is keep your mouth shut,” said David A. Harris, a law professor at University of Pittsburgh and an expert on police misconduct.
From Los Angeles Times ● Aug. 11, 2026
"This is a colossal opening," said analyst David A. Gross of Franchise Entertainment Research.
From Barron's ● Aug. 2, 2026
A. I was comparing notes with Adam Chandler, our food columnist and resident expert on food and dining trends, and he has noticed a hypervigilance around what people are serving—from chefs and caterers to influencers.
From The Wall Street Journal ● Jul. 31, 2026
It is Exhibit A. A guarantee that demands this much luck, money, and endurance before a court will enforce it has not been functioning as a guarantee.
From Slate ● Jul. 28, 2026
Mr. A. H— moves along the periphery, going mostly unnoticed and speaking with only a few of the other guests, including Mr. Barris, who introduces him to Herr Thiessen.
From "The Night Circus" by Erin Morgenstern
![]()
You know, that’s actually the easiest of all things, if you look, cause it’s such a–
From Slate ● Jan. 22, 2020
The montage ends with a honest rap from Issa: “I don’t want to be here, but my ex won’t take me back. So my broken a– is here, small-talking over apps.”
From Washington Post ● Jul. 28, 2017
We created a– civilian review board, gave them their own detectives.
From Time ● Jan. 17, 2016
MELBER: Now your path here– involved time as a– as a lawyer and a prosecutor.
From MSNBC ● Feb. 12, 2015
But whatever happens, you’ll 240 believe I’ve done my best, won’t you?–even if I’m not a– Promise me straight, you’ll lock up tight every night.”
From Into the Primitive by Robert Ames Bennett
Louth, 20 years old, said he earned all A’s and one B in his first semester and doubted he would have worked as hard had the classes been pass/fail.
From The Wall Street Journal ● Aug. 11, 2026
In May, Harvard University faculty voted to approve a 20% cap on the number of A’s per undergraduate course in an effort to curb grade inflation.
From The Wall Street Journal ● Aug. 11, 2026
The A’s scored the final run on a wild pitch in the ninth.
From Los Angeles Times ● Jun. 30, 2026
In the same way a dismal class performance on a business school exam will still yield some A’s, curves also apply in the stock market when a company’s results aren’t necessarily jumping off the page.
From Barron's ● Jun. 29, 2026
I had obtained A’s and B’s in all the other subjects, but because I had failed Tsonga, which carried more weight, I had failed.
From "Kaffir Boy: An Autobiography" by Mark Mathabane
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As he left, Turner gave a brief faith-laced pep talk for a group of young Dream Center residents in the audience.
From Los Angeles Times ● Aug. 12, 2026
As a competitive runner, Julian Flieller relied on human coaches to time his splits and manage his training regime.
From The Wall Street Journal ● Aug. 12, 2026
As it turns out, this is only a golden city for some people – and they're not the ones developers had hoped to attract.
From BBC ● Aug. 11, 2026
As Manus confirmed its separation from Meta on Tuesday, AFP looks at the rise and fall of its Meta deal:
From Barron's ● Aug. 11, 2026
As I carry Ben’s tray toward the whispering trees, Grandma Sarah calls, “Good luck!”
From "Legendary Frybread Drive-In" by Cynthia Leitich Smith
![]()
Like other Romance languages, Spanish divides most endings of nouns into masculine o’s or feminine a’s.
From Washington Times ● Dec. 12, 2021
And then, every fourth January, we’re suddenly expected to say it, to spell it, to know where to place the u’s and a’s.
From New York Times ● Jan. 19, 2017
But there is no doubt who is the original source of the line, and his last name is spelled with two a's.
From Time Magazine Archive
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His accent, a resonant blend of broad a's, clipped consonants and superbly rounded r's, is the same accent he used for credit in Manhattan speakeasies 20 years ago.
From Time Magazine Archive
![]()
Dr. Finch rolled out the last name in Maycomb County accents: long a’s, i s, and a pause between syllables.
From "Go Set a Watchman: A Novel" by Harper Lee
![]()
Appeared in the August 12, 2026, print edition as 'The Datamaxxers Feeding Their Every Health Move to AI'.
From The Wall Street Journal ● Aug. 12, 2026
Should he decide to sell the Angels, the city could use the exemption as leverage in discussions with a new owner.
From Los Angeles Times ● Aug. 12, 2026
President Donald Trump has confirmed that he secretly swapped planes as he left a Nato summit in Turkey last month due to a possible threat.
From BBC ● Aug. 12, 2026
Now, they are supercharging their habits with AI systems that serve as hyperpersonalized health trainers and assistants.
From The Wall Street Journal ● Aug. 12, 2026
“May we go inside?” she asks innocently, as if she’s a child ready for a big adventure.
From "At Last She Stood" by Erin Entrada Kelly
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.