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  • ad
    ad
    noun
  • ad-
    ad-
    a prefix occurring in loanwords from Latin, where it meant “toward” and indicated direction, tendency, or addition: adjoin . Usually assimilated to the following consonant; see a-, ac-, af-, ag-, al-, an-, ap-, ar-, as-, at-.
  • -ad
    -ad
    a suffix occurring in loanwords from Greek denoting a group or unit comprising a certain number, sometimes of years: dyad; triad .
  • ad.
    ad.
    abbreviation
    adverb.
  • a.d.
    a.d.
    abbreviation
    in the year of the Lord; since Christ was born.
  • A.D.
    A.D.
    abbreviation
  • AD
    AD
    abbreviation
    anno Domini Compare BC
Synonyms

ad

1 American  
[ad] / æd /

noun

  1. advertisement.

  2. advertising.

    an ad agency.


ad 2 American  
[ad] / æd /

noun

Tennis.
  1. advantage.

  2. ad in, the advantage being scored by the server.

  3. ad out, the advantage being scored by the receiver.


ad 3 American  
[ad] / æd /

preposition

  1. (in prescriptions) to; up to.


ad- 4 American  
  1. a prefix occurring in loanwords from Latin, where it meant “toward” and indicated direction, tendency, or addition: adjoin . Usually assimilated to the following consonant; see a-, ac-, af-, ag-, al-, an-, ap-, ar-, as-, at-.


-ad 5 American  
  1. a suffix occurring in loanwords from Greek denoting a group or unit comprising a certain number, sometimes of years: dyad; triad .

  2. a suffix meaning “derived from,” “related to,” “concerned with,” “associated with” (oread ), introduced in loanwords from Greek (Olympiad; oread ), used sporadically in imitation of Greek models, as Dunciad , after Iliad .


-ad 6 American  
  1. variant of -ade: ballad .


-ad 7 American  
  1. Anatomy, Zoology. a suffix forming adverbs from nouns signifying parts of the body, denoting a direction toward that part: dextrad; dorsad; mediad .


ad. 8 American  

abbreviation

  1. adverb.

  2. advertisement.


a.d. 9 American  
Or A.D.

abbreviation

  1. in the year of the Lord; since Christ was born.

    Charlemagne was born in a.d. 742.


a.d. 10 American  

abbreviation

  1. before the day.


a.d. 11 American  

abbreviation

  1. after date.

  2. autograph document.


A.D. 12 American  

abbreviation

  1. active duty.

  2. anno Domini. Also a.d.

  3. art director.

  4. assembly district.

  5. assistant director.

  6. athletic director.

  7. average deviation.


AD 1 British  

abbreviation

  1. anno Domini Compare BC

    70 ad

  2. military active duty

  3. military air defence

  4. Dame of the Order of Australia

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

-ad 2 British  

suffix

  1. a group or unit (having so many parts or members)

    triad

  2. an epic poem concerning (the subject indicated by the stem)

    Dunciad

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

ad- 3 British  

prefix

  1. to; towards

    adsorb

    adverb

  2. near; next to

    adrenal

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

-ad 4 British  

suffix

  1. denoting direction towards a specified part in anatomical descriptions

    cephalad

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

ad 5 British  
/ æd /

noun

  1. short for advertisement

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

ad 6 British  
/ æd /

noun

  1. Brit equivalent: van.  short for advantage

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

ad 7 British  

abbreviation

  1. Andorra

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Usage

Because anno Domini means “in the year of the Lord,” its abbreviation a.d. was originally placed before rather than after a date: The Roman conquest of Britain began in a.d. 43 (or began a.d. 43). In edited writing, it is still usually placed before the date. But, by analogy with the position of b.c. “before Christ,” which always appears after a date ( Caesar was assassinated in 44 b.c. ), a.d. is also frequently found after the date in all types of writing, including historical works: The Roman emperor Claudius I lived from 10 b.c. to 54 a.d. Despite its literal meaning, a.d. is also used to designate centuries, being placed after the specified century: the second century a.d.

In strict usage, ad is only employed with specific years: he died in 1621 ad , but he died in the 17th century (and not the 17th century ad ). Formerly the practice was to write ad preceding the date ( ad 1621 ), and it is also strictly correct to omit in when ad is used, since this is already contained in the meaning of the Latin anno Domini (in the year of Our Lord), but this is no longer general practice. bc is used with both specific dates and indications of the period: Heraclitus was born about 540 bc ; the battle took place in the 4th century bc

Etymology

Origin of ad1

First recorded in 1795–1800; by shortening

Origin of ad2

First recorded in 1915–20; by shortening

Origin of ad3

From Latin

Origin of ad-4

< Latin ad, ad- (preposition and prefix) to, toward, at, about; cognate with at 1

Origin of -ad5

Greek -ad- (stem of -as ), specialization of feminine adjective-forming suffix, often used substantively

Origin of -ad7

From the Latin word ad toward, anomalously suffixed to the noun; introduced as a suffix by Scottish anatomist John Barclay (1758–1826) in 1803

Origin of a.d.9

From Latin annō Dominī

Origin of a.d.10

From Latin ante diem

Explanation

An ad is a commercial or a print promotion for some product or service. In other words, an ad is an advertisement. When a company uses print or broadcasting — newspapers, magazines, the Internet, or television, for example — to attempt to sell more of something, it's an ad. Though the word ad is an informal shortened form of advertisement, it's become more commonly used than the original. Those in the business of advertising have objected to this slang form ever since it was first used, around 1840.

Keep Reading on Vocabulary.com

Vocabulary lists containing ad

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:

Recent ad campaigns and short films have shown that AI video -- even when it includes human characters -- has crossed a real threshold.

From Barron's Jul. 22, 2026

Subsequently, according to the lawsuit, Eli Lilly noted in the ad that a higher-dose version of Wegovy wasn’t included in the study.

From The Wall Street Journal Jul. 21, 2026

Novo Nordisk claimed its main competitor in the weight-loss drug business had committed "multiple violations" of federal and state false advertising and unfair competition laws, through its nationwide ad campaigns.

From BBC Jul. 21, 2026

One ad cited by Novo in its lawsuit is called “Watch This: Head-to-Head,” which began airing in February, according to iSpot.tv.

From MarketWatch Jul. 21, 2026

“Bill, bill, ad . . . ,” Chip flipped through the stack, sounding more relieved with each letter that wasn’t a plain envelope addressed to him, without a return address.

From "Found" by Margaret Peterson Haddix

What’s more, the Cardinals are surging and better with ad- dition of Zach Ertz.

From Los Angeles Times Oct. 21, 2021

The new party was founded to “boldly ad- dress their issues, the war in Vietnam, the militarization of society, the problems of the poor, and the destruction of the environment,” the party’s website proclaims.

From Salon Dec. 31, 2015

From Aesop’s Fables to Arabian Nights, many classic stories are about ad- venture and quests.

From MSNBC Sep. 9, 2014

He must be backstage in case something goes wrong and he has to ad- lib.

From BusinessWeek Feb. 22, 2012

NOTE.—The forms ac-, af-, etc., are euphonic variations of ad-, and follow generally the rule that the final consonant of the prefix assimilates to the initial letter of the root.

From New Word-Analysis by William Swinton

Gay = gaj‑a; gloomy = malgaja; suf. -ad denotes continuance.

From International Language Past, Present and Future: With Specimens of Esperanto and Grammar by Clark, Walter John

To roll = rul‑i; suf. -ad denotes continuance. 9Weariness.

From International Language Past, Present and Future: With Specimens of Esperanto and Grammar by Clark, Walter John

To make sick = naŭz‑i; -ad denotes continuation. 8Tired of.

From International Language Past, Present and Future: With Specimens of Esperanto and Grammar by Clark, Walter John

The banner, which uses the neo-fascist group‘s signature colors, also references the hot-button American Eagle ad. “She has the best blue genes,” the banner says.

From Los Angeles Times Aug. 8, 2025

“It’s from an old Budweiser ad. Yeah. It reminds me of that other famous Churchill quote, ‘Wazzzuuuuuuup?’”

From New York Times Jan. 23, 2024

“We hear you today. We must hear you tomorrow. There are less than 8 million Jewish people in this country. Fewer than are watching this ad. They need you to add your voice.”

From Seattle Times Oct. 30, 2022

“I had posted an ad. I had arranged to meet him,” said Strausbaugh, 28, of Heidelberg Township, shifting in her seat as she recounted the details of her case.

From Washington Times May 25, 2019

“You sound like a Wisconsin dairy ad. They’d be so proud.”

From "Amina's Song" by Hena Khan

The first exhibit of ancient glass in the New York museum’s history, “Ennion: Master of Roman Glass” features pieces dating from the early 1st century a.d. by Ennion, the era’'s preeminent maker of mold-blown glass.

From Architectural Digest Dec. 11, 2014

One Ennion jug, now fragmentary, survived a fire during the Roman capture of Jerusalem in a.d.

From Architectural Digest Dec. 11, 2014

By the end of the first millennium a.d.,

From "1491" by Charles C. Mann

Nonetheless, archaeological investigation has generally borne them out: the Inka seem indeed to have migrated to Qosqo from somewhere else, perhaps Lake Titicaca, around 1200 a.d.

From "1491" by Charles C. Mann

He has written that by 1000 a.d. the city had a population of as much as 115,000, with another quarter million in the surrounding countryside—numbers that Paris would not reach for another five centuries.

From "1491" by Charles C. Mann

“In the 14th century A.D., a Moroccan explorer named Ibn Battuta documented that a buttery variation of khichuri was eaten daily in South Asia,” wrote Rachael Grow for Mashed.

From Salon Jun. 7, 2026

Think of the centurions who cast lots for Christ’s robes on the day of the Crucifixion in 33 A.D.

From The Wall Street Journal May 19, 2026

Visitors to the Getty Villa in Los Angeles—the oceanside site of the J. Paul Getty Museum’s antiquities collection—have good reason to curse Theodosius as they gaze upon the sublime portrait of Isidora, painted around A.D.

From The Wall Street Journal Feb. 20, 2026

The noted Roman naturalist and historian was indeed an early expert in fermentation, yet he also wrote about “sal ammoniac” — yes, smelling salts — in his encyclopedic work “Natural History,” published in 79 A.D.

From Los Angeles Times Jan. 12, 2026

But plague didn’t begin to hit Europe with full force as the Black Death epidemics until A.D.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond

“I was moving away from Venus for the first time in my life, so I wanted it to be really meaningful,” Williams explained to AD while discussing the project.

From MarketWatch Jun. 8, 2026

The Council of Nicaea in 325 AD was, among other things, the first large-scale institutional exercise in theological fact-checking.

From The Wall Street Journal May 29, 2026

Athleticism in the post: JaVale McGee and Dwight Howard who could play with or for AD.

From Los Angeles Times May 12, 2026

The 105 previous Archbishops of Canterbury, from St Augustine in 597 AD, have all been men.

From BBC Mar. 25, 2026

On a nearby rock cliff, a crew member painted a memorial, a potential headstone for them all, Advance, AD 1853–1854.

From "American Spirits" by Barb Rosenstock

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