holster (n.)

"leather case for a pistol," 1660s, probably from Old English heolster, earlier helustr "concealment, hiding place," from Proto-Germanic *hulfti- (source also of Old High German hulft "cover, case, sheath," Old Norse hulstr "case, sheath," Middle Dutch holster, German Halfter "holster"), from PIE root *kel-(1) "to cover, conceal, save." Intermediate forms are wanting, and the modern word could as well be from the Norse or Dutch cognates.

holster (v.)

by 1902, from holster (n.). Related: Holstered; holstering.