belt vs holster

belt and holster both are nouns.

Word	Noun	Adjective	Verb	Adverb
belt	Yes	No	Yes	No
holster	Yes	No	No	No

As nouns, holster is a hyponym of belt; that is, holster is a word with a more specific, narrower meaning than belt:

belt (noun)	holster (noun)
the act of hitting vigorously	a sheath (usually leather) for carrying a handgun
a band to tie or buckle around the body (usually at the waist)	a belt with loops or slots for carrying small hand tools
endless loop of flexible material between two rotating shafts or pulleys
ammunition (usually of small caliber) loaded in flexible linked strips for use in a machine gun
a vigorous blow
an elongated region where a specific condition or characteristic is found
a path or strip (as cut by one course of mowing)