Merriam-Webster's Collegiate® Dictionary, 11th Edition
EVENING
I. noun
Usage: often attributive
Etymology: Middle English, from Old English ǣfnung, from ǣfnian to grow toward evening, from ǣfen evening; akin to Old High German āband evening and perhaps to Greek epi on Date: before 12th century
1. the latter part and close of the day and early part of the night, afternoon , the period from sunset or the evening meal to bedtime, the latter portion, the period of an evening's entertainment,
II. adjective
Date: 1797
suitable for formal or semiformal evening social occasions