-
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:
At the time, Labour's deputy leader Jack Hemmingway said the government was providing £17.9m towards redeveloping the area, describing it as "a once in a generation opportunity to transform the city centre".
From BBC ● Aug. 27, 2026
The drone factory in Mildenhall was opened in February and is run by Ukrspecsystems, a Ukrainian firm.
From BBC ● Aug. 27, 2026
Despite the disruption caused by the war in the Middle East, almost 300,000 extra travellers took flights compared with the same period last year, a 4% increase.
From BBC ● Aug. 27, 2026
Before May, he was a businessman who would drive around his home city of Wakefield wishing the potholes could be fixed.
From BBC ● Aug. 27, 2026
If she wants to leave again, he says, she will have to provide a “complete understanding relative to her movements.”
From "At Last She Stood" by Erin Entrada Kelly
![]()
A dedicated e-commerce facility has processed more than 33 million parcels since opening in May last year, with Royal Mail and Evri establishing on-site operations.
From BBC ● Aug. 27, 2026
"My mother had regrets about my birth, and I was driven to the edge psychologically," she wrote in her autobiography, "A Personal History of Polka Dots".
From Barron's ● Aug. 27, 2026
A spokeswoman for JPMorgan said no such conversation ever occurred.
From The Wall Street Journal ● Aug. 27, 2026
A man who allegedly terrorized Philadelphia residents while wearing a creepy Halloween mask has been arrested in Las Vegas.
From Los Angeles Times ● Aug. 27, 2026
A doctor is bound by his oath not to reveal the details of a patient's condition without permission, so Dr. Harlow will keep his observations to himself for twenty years.
From "Phineas Gage" by John Fleischman
![]()
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
The main deviations from this fit are two absorption-like lines at 8,100 Å and 12,300 Å that evolve with time and become more pronounced in the second spectrum.
From Nature ● Oct. 15, 2017
FORS2 spectra were acquired with the 600B and 600RI grisms, covering the 3,500–8,600 Å wavelength range fully.
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
Continue round into Glen Pean and up to the Bealach a’ Chaorainn.
From The Guardian ● Feb. 29, 2020
“Oh lord, Sierra, really? Everybody has a little gut, and plenty a’ dudes go crazy for ’em.
From "Shadowshaper" by Daniel José Older
![]()
And Robert Heath was sort of a- adventurous entrepreneur of a neurologist and psychiatrist.
From Scientific American ● May 4, 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
![]()
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
In person, you do things like a basic fitness test -a bleep test - but you don't need qualifications.
From BBC ● Apr. 12, 2022
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
The eyes of some animal peer at me from the neighboring tree -a possum maybe -catching the firelight from the Careers' torches.
From "The Hunger Games" by Suzanne Collins
![]()
At the University of Michigan, a review by the news site MLive found that 74.1% of all undergraduate grades in 2022 were an A+, A or A-.
From The Wall Street Journal ● Aug. 11, 2026
"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
The difference between an A- and an A+, according to the report, could depend on how much spring precipitation the region receives.
From Los Angeles Times ● May 12, 2024
Normally it’s sort of fun to count the A- , B-, and Z-listers shilling for mayonnaise and sneakers.
From Slate ● Feb. 12, 2024
I charged a dollar per assignment and guaranteed at least an A- or the customer was entitled to a full refund.
From "The Glass Castle" by Jeannette Walls
![]()
This makes sense as 1 = loga a means a1 = a. which is true for any a.
From Textbooks ● May 6, 2020
Using a. and b. is the train speeding up or slowing down?
From Textbooks ● Mar. 30, 2016
From part a. we see that receiving $1.5 million dollars over the course of 20 years is worth $18.693 million dollars in today’s dollars.
From Textbooks ● Mar. 30, 2016
Rewrite the integral in part a. as an equivalent integral in five other orders.
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
![]()
My father, Vilas A. Jones, was mayor of Tarkio, in neighboring Atchison County, until shortly before his death in 2002.
From The Wall Street Journal ● Aug. 26, 2026
Freeman, on the other hand, started the season in triple A. But that didn’t split up the roommates.
From Los Angeles Times ● Aug. 25, 2026
They suggest that A. syrax could become a flagship species for conservation in the region, joining other rare animals found there, including the Asian forest tortoise, Oldham's leaf turtle and the Indochinese tiger.
From Science Daily ● Aug. 24, 2026
Dan A. Sullivan -- or, as he puts it, the original Sullivan.
From Barron's ● Aug. 24, 2026
“Good to be back in the good old U.S. of A. Hamburgers sizzling on an open grill and all that. Land of Opportunity. Long may she wave.”
From "The Secret History" by Donna Tartt
![]()
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
Seriously, the dude’s shrieks could be heard echoing in the A’s dugout on the NBC Sports California broadcast of the game.
From Los Angeles Times ● Jul. 1, 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
In fact, he had seldom received a mark lower than an A. In the seventh and eighth grades at St. Jude’s, he had received straight A's for two years except for a 5-plus one term.
From "The Chocolate War" by Robert Cormier
![]()
As Herrera's career progressed and he became a senior player in dressing rooms, he saw the effect social media can have on younger players.
From BBC ● Aug. 27, 2026
As a result, she said she learned early on to draw at a feverish pace, and she remained prolific throughout her life.
From The Wall Street Journal ● Aug. 27, 2026
"As climate change is affecting things, and it gets more intense, the challenges become greater," he said.
From Barron's ● Aug. 27, 2026
As open-source artificial intelligence gains momentum, Nvidia may be making a sizable acquisition.
From MarketWatch ● Aug. 27, 2026
As soon as she was ready, Maggie drug her out to stand in front of another Osage family’s cornfield so she could shoot a few portraits.
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
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
![]()
It kept reading my a's as g's or u's, my b's as d's and sprinkling periods liberally throughout my text.
From Time Magazine Archive
![]()
He turned red, thinking of his trouble with long a’s, th’s, l’s, consonants at the ends of words.
From "Typical American" by Gish Jen
![]()
The MoD said it would not comment on specific security procedures as this could benefit potential adversaries, but it said the security of defence assets was a top priority for the Labour government.
From BBC ● Aug. 27, 2026
At the time, Labour's deputy leader Jack Hemmingway said the government was providing £17.9m towards redeveloping the area, describing it as "a once in a generation opportunity to transform the city centre".
From BBC ● Aug. 27, 2026
At the time, it said it had repurposed a building in order to produce the unmanned aircraft as part of a £200m investment.
From BBC ● Aug. 27, 2026
The young Ander watched from home as his team beat Arsenal to clinch the trophy in the Parc des Princes, the home of PSG - a club he later spent three years at.
From BBC ● Aug. 27, 2026
Joey soldiers on, as she always does, but there is plenty to worry about.
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.