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  1. advertisement.
  2. advertising: an ad agency.

Origin of ad1

First recorded in 1835–45; by shortening
Can be confusedad add oddadds ads adz


noun Tennis.
  1. advantage(def 5).
  2. ad in, the advantage being scored by the server.
  3. ad out, the advantage being scored by the receiver.

Origin of ad2

First recorded in 1945–50; by shortening


  1. (in prescriptions) to; up to.

Origin of ad3

From Latin


  1. adverb.
  2. advertisement.


  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-5, ac-, af-, ag-, al-, an-2, ap-1, ar-, as-, at-.

Origin of ad-

< Latin ad, ad- (preposition and prefix) to, toward, at, about; cognate with at1


or A.D.

  1. in the year of the Lord; since Christ was born: Charlemagne was born in a.d. 742.

Origin of a.d.1

From the Latin word annō Dominī

Usage note

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.


  1. before the day.

Origin of a.d.2

From the Latin word ante diem


  1. after date.
  2. autograph document.


  1. active duty.
  2. art director.
  3. assembly district.
  4. assistant director.
  5. athletic director.
  6. average deviation.


  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.

Origin of -ad1

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


  1. variant of -ade1: ballad.


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

Origin of -ad3

From the Latin word ad toward, anomalously suffixed to the noun; introduced as a suffix by Scottish anatomist John Barclay (1758–1826) in 1803
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for ad

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Historical Examples

British Dictionary definitions for ad


  1. short for advertisement


noun tennis, US and Canadian
  1. short for advantage Brit equivalent: van


the internet domain name for
  1. Andorra


abbreviation for
  1. (indicating years numbered from the supposed year of the birth of Christ) anno Domini70 ad Compare BC
  2. military active duty
  3. military air defence
  4. Dame of the Order of Australia

Word Origin

(sense 4) Latin: in the year of the Lord


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


  1. to; towardsadsorb; adverb
  2. near; next toadrenal

Word Origin

from Latin: to, towards. As a prefix in words of Latin origin, ad- became ac-, af-, ag-, al-, an-, acq-, ar-, as-, and at- before c, f, g, l, n, q, r, s, and t, and became a- before gn, sc, sp, st


suffix forming nouns
  1. a group or unit (having so many parts or members)triad
  2. an epic poem concerning (the subject indicated by the stem)Dunciad

Word Origin

via Latin from Greek -ad- (plural -ades), originally forming adjectives; names of epic poems are all formed on the model of the Iliad


suffix forming adverbs
  1. denoting direction towards a specified part in anatomical descriptionscephalad

Word Origin

from Latin ad to, towards
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

Word Origin and History for ad


1841, shortened form of advertisement. Long resisted by those in the trade, and denounced 1918 by the president of a national advertising association as "the language of bootblacks, ... beneath the dignity of men of the advertising profession."


1570s, from Latin Anno Domini "Year of the Lord." First put forth by Dionysius Exiguus in 527 or 533 C.E., but at first used only for Church business. Introduced in Italy in 7c., France (partially) in 8c. In England, first found in a charter of 680 C.E. Ordained for all ecclesiastical documents in England by the Council of Chelsea, July 27, 816.

The resistance to it in part might have come because Dionysius chose 754 A.U.C. as the birth year of Jesus, while many early Christians would have thought it was 750 A.U.C. [See John J. Bond, "Handy-Book of Rules and Tables for Verifying Dates With the Christian Era," 4th ed., London: George Bell & Sons, 1889] A.C., for Anno Christi, also was common 17c.


word-forming element expressing direction toward or in addition to, from Latin ad "to, toward" in space or time; "with regard to, in relation to," as a prefix, sometimes merely emphatic, from PIE *ad- "to, near, at" (cognate with Old English æt; see at). Simplified to a- before sc-, sp- and st-; modified to ac- before many consonants and then re-spelled af-, ag-, al-, etc., in conformity with the following consonant (e.g. affection, aggression). In Old French, reduced to a- in all cases (an evolution already underway in Merovingian Latin), but written forms were refashioned after Latin in 14c. in French and 15c. in English words picked up from Old French. In many cases pronunciation followed the shift.


word-forming element denoting collective numerals (cf. Olympiad), plant families, and names of poems, from Greek -as (genitive -ados), a suffix forming fem. nouns; also used in fem. patronymics (Dryad, Naiad, also, in plural, Pleiades, Hyades).

Online Etymology Dictionary, © 2010 Douglas Harper

ad in Medicine


  1. auris dextra (right ear)


  1. Toward; to. Before c, f, g, k, l, p, q, s, and t, ad- is usually assimilated to ac-, af-, ag-, ac-, al-, ap-, ac-, as-, and at-, respectively:adductor, acclimation, agglutinant.
  2. Near; at:adrenal.


  1. In the direction of; toward:cephalad.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

ad in Culture


An abbreviation used with a date, indicating how many years have passed since the birth of Jesus. The abbreviation may appear before the date (a.d. 1988), or it may appear after the date (1988 a.d.). It stands for anno Domini, a Latin phrase meaning “in the year of our Lord.” (Compare b.c.)

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.