-
a
aindefinite articlenot any particular or certain one of a class or group.
-
A
Anounthe first letter of the English alphabet, a vowel.
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Å
Åangstrom.
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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
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(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.
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(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:
In a joint "letter of concern" to the Northern Ireland Executive, four hospital campaign groups have called for a cross-departmental working group on rural health access.
From BBC ● Oct. 19, 2026
The groups called for a "presumption of restoration" - a pathway to restore services in cases where they were removed from rural hospitals without the appropriate assessments or scrutiny.
From BBC ● Oct. 19, 2026
They said they believed that a safe, secure and sustainable home should include access to the basic furniture necessary for everyday living.
From BBC ● Oct. 19, 2026
It is not a problem confined to one area.
From BBC ● Oct. 19, 2026
After reading about Joey’s bravery during the war and her arrival in the US, he’s inspired to start a fund drive called Joey’s International Leprosy Fund.
From "At Last She Stood" by Erin Entrada Kelly
![]()
A Facebook advert we saw had one man "looking for 7/8 ghost tenants in various houses of mine".
From BBC ● Oct. 19, 2026
A Two Sigma spokeswoman said the firm’s assets under management are at a record high, investor demand remains strong, and the current year’s performance ranks among the its best.
From The Wall Street Journal ● Oct. 19, 2026
A corrections department board two years ago moved to grant Luster’s early release on parole, over the objections of all three victims, who appeared at the hearing and spoke against a release.
From Los Angeles Times ● Oct. 19, 2026
A spokesperson told the AFP news agency there were 51 passengers and six crew members on board the jet.
From BBC ● Oct. 19, 2026
A few yards behind Phineas, a group of his men are using a hand-cranked derrick crane to hoist a large piece of rock.
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
At the first epoch, all deviations from the blackbody spectrum are below about 10% in the range 3,500 Å–20,000 Å, indicating that the fit is very satisfactory.
From Nature ● Oct. 15, 2017
The backbone amide hydrogen bonds maintain the β-strands at a spacing of 4.8 Å in the direction of the fibril.
From Nature ● Nov. 8, 2016
Some songs—such as “A Guid New Year to ane a’ A’”—were widely recognized.
From National Geographic ● Dec. 27, 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
“You might not wanna believe it, but things, they are a’ changing,” he said.
From Washington Times ● Nov. 1, 2016
“Oh lord, Sierra, really? Everybody has a little gut, and plenty a’ dudes go crazy for ’em.
From "Shadowshaper" by Daniel José Older
![]()
Katie Hafner: In fact, they call it kind of a- a triangle of –
From Scientific American ● Sep. 21, 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
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
‘I’m not -a thief!’ coughed Torak, snatching at his throat.
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
“Mandalorian” got an average grade of A- from audiences, according to market research firm CinemaScore.
From The Wall Street Journal ● May 24, 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
“Frozen Empire” garnered a B+ CinemaScore from moviegoers, a tick down from the A- score for “Afterlife.”
From Seattle Times ● Mar. 24, 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
![]()
Evaluate a. and b. for t = 2, 4, and 6 seconds.
From Textbooks ● Mar. 30, 2016
Find the derivative of the equation in a. and explain its physical meaning.
From Textbooks ● Mar. 30, 2016
For the following exercises, a. find the inverse function, and b. find the domain and range of the inverse function.
From Textbooks ● Mar. 30, 2016
Determine the equation and sketch the trace of the ring torus from a. on the xy-plane.
From Textbooks ● Mar. 30, 2016
When a. filovirus begins to amplify itself in a human being, the incubation period is from three to eighteen days, while the number of virus particles climbs steadily in the bloodstream.
From "The Hot Zone" by Richard Preston
![]()
A. I was most surprised by their answers on AI.
From The Wall Street Journal ● Oct. 16, 2026
"Patients may accumulate amyloid for years before symptoms appear," said first author Christopher A. Brown, MD, PhD, an assistant professor of Neurology.
From Science Daily ● Oct. 15, 2026
“Every child deserves to feel safe and never be victimized by someone they trust,” said Robert A. Eikhoff, special agent in charge of the FBI Jackson Field Office in Mississippi.
From Los Angeles Times ● Oct. 15, 2026
The film triumphed despite poor reviews and audience reception, according to analyst David A. Gross of Franchise Entertainment Research.
From Barron's ● Oct. 11, 2026
I was sprawled on the rug in the living room, reading The Voyage of the Space Beagle by A. E. van Vogt.
From "October Sky" by Homer Hickam
![]()
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
Other parents’ choices didn’t cause Najya’s teachers to leave assignments uncorrected, lower expectations, or award A’s for below-grade work.
From The Wall Street Journal ● Sep. 23, 2026
Grade inflation has become so endemic that 44% of students who scored below 1000 on the SAT—roughly the bottom half—reported receiving all or mostly A’s.
From The Wall Street Journal ● Sep. 13, 2026
“All achievements — straight A’s at the time — anything that could be rewarded was pooled to funds,” he said, reclining on a patio chair in the shade at Chargers headquarters.
From Los Angeles Times ● Sep. 7, 2026
With A’s on his report card and the energy and determination to never stop improving, Benson is headed on a path that could take him in many different directions.
From Los Angeles Times ● Sep. 6, 2026
"Just go along the A's until you come to A-R."
From "Freak The Mighty" by Rodman Philbrick
![]()
As the emotional storms begin to break out, it’s easy to sympathize with Trip, whose exasperation Mr. Keery captures with dynamic energy and bruising humor.
From The Wall Street Journal ● Oct. 19, 2026
She doesn’t disappoint: As Polly presides over a fractious Christmas gathering, she deftly slashes to ribbons her lovably flawed loved ones even as she flashes a mile-wide grin.
From The Wall Street Journal ● Oct. 19, 2026
"As soon as he struck it, I knew it was in. He's taken the club goal of the season off me," joked Brighton skipper Dunk.
From BBC ● Oct. 18, 2026
As a result, hundreds of women were affected, and many were compelled to resign.
From Los Angeles Times ● Oct. 18, 2026
As luck would have it, a neighbor of his was traveling the same road, on business.
From "Adventures of Don Quixote" by Argentina Palacios
![]()
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
![]()
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
![]()
In the court documents, several are referred to as "unknown male child" and identified by the location of their grave and date of their discovery.
From BBC ● Oct. 19, 2026
She doesn’t disappoint: As Polly presides over a fractious Christmas gathering, she deftly slashes to ribbons her lovably flawed loved ones even as she flashes a mile-wide grin.
From The Wall Street Journal ● Oct. 19, 2026
They have called for independent rural-needs and equality assessments, as well as a cross-departmental ministerial working group on rural health access.
From BBC ● Oct. 19, 2026
He started going to Mackenzie's church when he was eight years old and described him as his "spiritual father", adding that he would "never say a bad word about him".
From BBC ● Oct. 19, 2026
Captain Colayco is celebrated as a great freedom fighter.
From "At Last She Stood" by Erin Entrada Kelly
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Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.