Quiz: Remember the definition of mal de mer?
late 14c., "the evening star," from Old French vespre, from Latin vesper (masc.), vespera (fem.) "evening star, evening, west," related to Greek hesperos, and ultimately from PIE *wespero- (cf. Old Church Slavonic večeru, Lithuanian vakaras, Welsh ucher, Old Irish fescor "evening"), from root *we- "down" (cf. Sanskrit avah "down, downward"). Meaning "evening" is attested from c.1600.
Vespers "sixth canonical hour" is attested from 1610s, from plural of Latin vespera "evening;" the native name was evensong (Old English æfen-sang).