-
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:
The Chinese company will be the first to market in a wave of new humanoid-robotics IPOs.
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
Established in 2021, Turing is a relatively new entrant to the autonomous-driving landscape.
From The Wall Street Journal ● Aug. 12, 2026
As an example of money wasted by LAHSA’s lack of financial controls, Turner cited the recent federal indictment alleging a homeless services provider fleeced the system of $23 million in fraudulent billings.
From Los Angeles Times ● Aug. 12, 2026
In June 1969, Joey graduates from college and is accepted into graduate school at Middlebury College, where she earns a master’s degree in Spanish literature.
From "At Last She Stood" by Erin Entrada Kelly
![]()
A stronger print could reinforce a tighter policy and add further pressure to gold, says Tony Sage, CEO of Critical Metals, in a note.
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 solar eclipse happens when the Earth, Moon and the Sun align - or almost align.
From BBC ● Aug. 11, 2026
A StubHub spokesperson said about 1% of orders result in a refund.
From The Wall Street Journal ● Aug. 11, 2026
A deep, roaring wail bursts out of me.
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
Two or more such β-sheets lie in parallel, 6–12 Å apart.
From Nature ● Nov. 8, 2016
Here we present the 3.7 Å resolution cryo-electron microscopy structure of ZIKV, and show that the overall architecture of the virus is similar to that of other flaviviruses.
From Nature ● Apr. 18, 2016
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
Bob Dylan’s “The Times They Are a’ Changin’” is “a little bit sad and I think it’s about friends,” he wrote.
From Washington Times ● Oct. 8, 2016
“Good yer takin’ a taxi, ’stead a’ the subway,” the Cap’n says to us, but it’s me he’s looking at with his one good eye.
From "Challenger Deep" by Neal Shusterman
![]()
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
The thin wooden door split with a- thunderous ciack beneath the heel of Shagga's boot.
From "A Clash of Kings" by George R.R. Martin
![]()
Usually words ending in "-o" are masculine and those ending in "-a" are feminine, but there are many common words that break those gender rules, like "la mano," the word for "hand."
From Salon ● Sep. 26, 2022
One of those is Zhima Credit – -a private credit-scoring system that rates the trustworthiness and creditworthiness of its users based on data such as whether users pay their bills on time via Alipay.
From Washington Times ● Oct. 27, 2020
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
Even the rushlight turned black -a black flame flaring above him ...
From "Wolf Brother" by Michelle Paver
![]()
"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
Incredibly, one in 12 lacked middle-school math skills, and 94% had completed an advanced math course and received an average A- in their high-school math classes.
From The Wall Street Journal ● May 28, 2026
Normally it’s sort of fun to count the A- , B-, and Z-listers shilling for mayonnaise and sneakers.
From Slate ● Feb. 12, 2024
The film currently sits with a 96% rating from critics and a 91% audience score at review aggregate site Rotten Tomatoes as well as an A- in the poll from CinemaScore.
From Los Angeles Times ● Dec. 10, 2023
I put on my high heels, a gray A- line dress that I had made myself, and a little bit of lipstick.
From "Reaching for the Moon" by Katherine Johnson
![]()
This makes sense as 1 = loga a means a1 = a. which is true for any a.
From Textbooks ● May 6, 2020
Use a. to find the rate at which the volume is changing at t = 1 min.
From Textbooks ● Mar. 30, 2016
Rewrite the integral in part a. as an equivalent integral in five other orders.
From Textbooks ● Mar. 30, 2016
Use your answers to parts a. and d. to determine which of the three options is best.
From Textbooks ● Mar. 30, 2016
Was Diego a nice boy who sometimes lost his temper or a. monster who’d mastered pretending to be nice?
From "We Are the Ants" by Shaun David Hutchinson
![]()
“Versions of this case have played out in federal courts across the country,” Judge Daniel A. Bress wrote for the 9th Circuit on Thursday.
From Los Angeles Times ● Jul. 31, 2026
A. As a native New Yorker, I grew up with countless cuisines just a subway ride away.
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
Not an A. No, because not every assignment has been completed.
From Los Angeles Times ● Jul. 28, 2026
We were cleaning A. J. Diany, a construction office, and he was whistling and singing like a canary.
From "Breaking Through" by Francisco Jiménez
![]()
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
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
He had always been a good student, securing almost all A’s with a few Bs sprinkled in.
From Los Angeles Times ● Jul. 26, 2026
Palestra spent last season on loan at Cagliari and was named Serie A's defender of the year.
From BBC ● Jul. 1, 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
My high school offered a creative writing course, but in order to get in you had to have straight A's in eleventh-grade English.
From "Hole in My Life" by Jack Gantos
![]()
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 recently as last week, Ellison met with top executives at the company to outline a possible fall move, according to a person familiar with the matter.
From The Wall Street Journal ● Aug. 12, 2026
As it enters Assam's vast floodplains, home to some 28 million people and hemmed in by hills, it slows and deposits sediment, fuelling erosion and floods.
From BBC ● Aug. 11, 2026
"As migrants, we've already been through some tough things back in our own country, and you never imagine something like this would happen on top of that," said the 28-year-old construction worker.
From Barron's ● Aug. 11, 2026
As a rule, wandering souls were never able to cross the threshold into Clare’s cottage unless they were invited.
From "The Undead Fox of Deadwood Forest" by Aubrey Hartman
![]()
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
![]()
As a foriner, ce hardest cing in English to lern is ce usage of ce's and a's.
From Time Magazine Archive
![]()
“He spells it with one a. The two a’s seem a little fancy to his friends.”
From "East of Eden" by John Steinbeck
![]()
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
Both Turner and Kennedy endorsed faith-based recovery programs as alternatives preferred by the administration over “housing first.”
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
Panumre Liberum argue that copper offers gold’s inflation protection, plus an industrial-backed demand growth story, as well as a relative immunity to movements in interest rates.
From The Wall Street Journal ● Aug. 12, 2026
We know she was less than five feet tall and fewer than one hundred pounds, yet tough enough to cross battlefields as bullets rained around her.
From "At Last She Stood" by Erin Entrada Kelly
![]()
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.