Main Entry: vail

Pronunciation: \ˈvāl\

Function: transitive verb

Etymology: Middle English valen, partly from Anglo-French valer (short for avaler to lower) & partly short for Middle English avalen to let fall, from Anglo-French avaler, from aval downward, from a to (from Latin ad) + val valley — more at at, vale

Date: 14th century

: to lower often as a sign of respect or submission