the word 'valley' descends from the latin 'vallis', which denoted a hollow or depression between hills. this term passed into old french as 'valee', and was subsequently adopted into middle english as 'valey' from anglo-french. the core concept of a low-lying geographical feature has remained remarkably consistent from its latin root to its present-day meaning. the modern spelling with 'ey' solidified in the late middle english period, standardizing the form for the enduring natural feature it describes.

the word is a simplex unit. it originates from the anglo-french word 'valey', which came from the old french 'valee', based on the latin 'vallis' meaning 'valley'. the modern english spelling 'valley' reflects a later anglicization.