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a.d.1

or A.D.

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

a.d.2

  1. before the day.
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Origin of a.d.2

From the Latin word ante diem

a.d.3

  1. after date.
  2. autograph document.
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A.D.

  1. active duty.
  2. art director.
  3. assembly district.
  4. assistant director.
  5. athletic director.
  6. average deviation.
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Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Word Origin and History for a.d.

A.D.

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.

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Online Etymology Dictionary, © 2010 Douglas Harper

a.d. in Culture

A.D.

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.)

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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.