Definition of week evening in US English:

week evening

noun

  • A weekday evening; specifically (in early use) an evening of the week other than Sunday evening; (now usually) an evening of the working week; an evening other than Saturday or Sunday evening (sometimes also excluding Friday evening); frequently attributive.

Origin

Late 18th century; earliest use found in Thomas Coke (1747–1814), Church of England clergyman and founder of Methodist missions.