river-land between two ranges of hills, early 14c., from Old French val "valley, vale" (12c.), from Latin vallem (nominative vallis, valles) "valley" (see valley). Now "little used except in poetry" [Century Dictionary]. Vale of years "old age" is from "Othello." Vale of tears "this world as a place of trouble" is attested from 1550s. An older phrase in the same sense was dale of dol (mid-15c.).
level or gently sloping ground between low hills with a stream flowing through it, Old English dæl "vale, valley, gorge," from Proto-Germanic *dalaz "valley" (source also of Old Saxon, Dutch, Gothic dal, Old Norse dalr, Old High German tal, German Tal "valley"), perhaps from PIE *dhel- "a hollow" (source also of Old Church Slavonic dolu "pit," Russian dolu "valley"), or perhaps a substratum word. It was preserved by Norse influence in the north of England. Related: Dalesman.
Folk etymology is from Medieval Latin carne vale " 'flesh, farewell!' " From 1590s in figurative sense "feasting or revelry in general." Meaning "a circus or amusement fair" is attested by 1926 in American English.