From Anglo-Norman 'valee,' from Latin 'vallis' — a landscape term that came through the Norman Conquest.
A low area of land between hills or mountains, typically with a river or stream flowing through it.
From Middle English 'valeye,' borrowed from Anglo-Norman 'valee' (Old French 'valee'), from Latin 'vallis' or 'vallēs' ('valley'). The Latin word is of uncertain deeper origin but may be related to PIE *wel- ('to turn, to roll'), referring to the way a valley curves between hills. English also inherited the more literary doublet 'vale' directly from Old French 'val,' so 'valley' and 'vale' are
English has two words from the same Latin source: 'valley' (from Old French 'valee,' the extended form) and the more poetic 'vale' (from Old French 'val,' the simpler form). 'Vale of tears' and 'Silicon Valley' thus share the same Latin root 'vallis,' though they evoke vastly different landscapes.