from the GNU version of the Collaborative International Dictionary of English
- adj. the present era, commencing with the birth of Christ. It is supposed that owing to an error of a monk (Dionysius Exiguus, d. about 556) employed to calculate the era, its commencement was fixed three or four years too late, so that 1890 should be 1893 or 1894.
- The era in use in all Christian countries, which was intended to commence with the birth of Christ. The era as now established was first used by Dionysius Exiguus (died about 540), who placed the birth of Christ on the 25th of December in the year of Rome 754, which year he counted as 1 a. d. This date for Christ's birth is now generally thought to be about four years too late.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the time period beginning with the supposed year of Christ's birth
Sorry, no etymologies found.