Etymology
From Dutch holster (“pistol-case, holster”), from Middle Low German holster, from Old Saxon *holster, ultimately from Proto-Germanic *hulastrą, *hulistrą (“hull, case, covering”).
Cognate with Old English heolstor (“a covering, veil, hiding-place”), Danish hylster (“pistol case, envelope”), Icelandic hulstur (“sheath”), Gothic 𐌷𐌿𐌻𐌹𐍃𐍄𐍂 (hulistr, “covering”). Compare German Halfter (“pistol case”). Related to hull, hele.