You use AD in dates to indicate the number of years or centuries that have passed since the year in which Jesus Christ is believed to have been born. Compare BC.
The cathedral was destroyed by the Great Fire of 1136 AD.
The original castle was probably built about AD 860.
The Roman Empire was divided in the fourth century AD.
ad in British English1
(æd)
noun
short for advertisement
ad in British English2
(æd)
noun tennis, US and Canadian
short for advantage. Brit equivalent: van
ad in British English3
the internet domain name for
Andorra
AD in British English
abbreviation for
1. (indicating years numbered from the supposed year of the birth of Christ)
anno Domini
70 ad
Compare BC
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
Word origin
(sense 4) Latin: in the year of the Lord
ad- in British English
prefix
1.
to; towards
adsorb
adverb
2.
near; next to
adrenal
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
-ad in British English1
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 modelof the Iliad
-ad in British English2
suffix forming adverbs
denoting direction towards a specified part in anatomical descriptions