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

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

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

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

variant of -ade¹: ballad.

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

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

adverb.

advertisement.

active duty.

in the year of the Lord; since Christ was born: Charlemagne was born in a.d. 742. Origin:
< Latin annō Dominī.

art director.

assembly district.

assistant director.

athletic director.

average deviation.

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.

after date.

before the day. Origin:
< Latin ante diem.

autograph document.

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2013.
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Link To ad

Collins

World English Dictionary

ad¹ (æd)

—n
	short for advertisement

ad² (æd)

—n
	short for advantage Brit equivalent: van

ad³

—*the internet domain name for*
	Andorra

AD

—*abbreviation for*
1.	Compare BC anno Domini: 70 ad
2.	military active duty
3.	military air defence
4.	Dame of the Order of Australia

usage 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

ad-

—*prefix*
1.	to; towards: adsorb; adverb
2.	near; next to: adrenal

[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]

-ad¹

—*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

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

-ad²

—*suffix forming adverbs*
	denoting direction towards a specified part in anatomical descriptions: cephalad

[from Latin ad to, towards]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Etymonline

Word Origin & History

A.D.

1570s, from L. 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 may have been in part 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]

ad-

prefix expressing direction toward or in addition to, from L. ad "to, toward," from PIE *ad- "to, near, at" (cognate with O.E. 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 O.Fr., reduced to a- in all cases, but written forms were refashioned after L. in 14c. in Fr., and 15c. in Eng. words picked up from O.Fr. In many cases pronunciation followed the shift.

-ad

suffix denoting collective numerals (cf. Olympiad), from Gk. -as (gen. -ados), a suffix forming fem. nouns; also used in fem. patronymics (Dryad, Naiad, also, in plural, Pleiades, Hyades).

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."

Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage

Medical Dictionary

AD abbr.
Latin auris dextra (right ear)

ad- pref.

or ac- or af- or ag- or al- or ap- or as- or at- 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.
Near; at: adrenal.

-ad suff.
In the direction of; toward: cephalad.

American Heritage

Cultural Dictionary

A.D. definition

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.)

FOLDOC

Computing Dictionary

AD definition

Administrative Domain

ad definition

networking
The country code for Andorra.
(1999-01-26)

American Heritage

Abbreviations & Acronyms

ad
advertisement

active duty
air-dried
Alzheimer's disease
athletic director
average deviation

ad.

adapter
adverb

a.d.

after date
Latin ante diem (before the day)
autograph document

A.D.

Latin anno Domini (in the year of our Lord)
Latin auris dexter (right ear)

Example sentences from the web

And then this designer would likewise need a designer, and so on ad infinitum.

Ad lib is specifically often used when someone improvises or ignores

limitations.

Hanson felt that the studio played it safe with the original ad campaign.

Among the exhibits is a much admired carved ivory bucket of the fourth century

ad.

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Matching Quote

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