early 14c., "at an early period;" late 14c., "seasonably, before it is too late," from betime (c. 1300, from be- + time (n.)). With adverbial genitive -s.
he awoke betimes that morning
Bethesda
bethink
Bethlehem
bethump
betide
betimes
betoken
betray
betrayal
betrayer
betroth