holster (n.) Look up holster at Dictionary.com
"leather case for a pistol," 1660s, probably from Old English heolster, earlier helustr "concealment, hiding place," from Proto-Germanic *hulfti- (cognates: Old High German hulft "cover, case, sheath," Old Norse hulstr "case, sheath," Middle Dutch holster, German Halfter "holster"), from PIE *kel- (2) "to cover, to hide" (see cell). Intermediate forms are wanting, and the modern word could as well be from the Norse or Dutch cognates.
holster (v.) Look up holster at Dictionary.com
by 1902, from holster (n.). Related: Holstered; holstering.