Definify.com
Webster 1913 Edition
Complin
{ 
, Com′pline
,Com′plin
}Noun.
 [From OE. 
complie
, OF. complie
, F. complies
, pl., fr. LL. completa 
(prop. fem. of L. completus
) the religious exercise which completes and closes the service of the day. See Complete
.] (Eccl.) 
The last division of the Roman Catholic breviary; the seventh and last of the canonical hours of the Western church; the last prayer of the day, to be said after sunset. 
The custom of godly man been to shut up the evening with a 
compline 
of prayer at nine of the night. Hammond.
Webster 1828 Edition
Complin
COMPLIN
,Noun.