ostomy vs colostomy

ostomy and colostomy both are nouns.

Word	Noun	Adjective	Verb	Adverb
ostomy	Yes	No	No	No
colostomy	Yes	No	No	No

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

ostomy: surgical procedure that creates an artificial opening for the elimination of bodily wastes
colostomy: a surgical operation that creates an opening from the colon to the surface of the body to function as an anus

Other hyponyms of ostomy include ileostomy.

ostomy (noun)	colostomy (noun)
surgical procedure that creates an artificial opening for the elimination of bodily wastes	a surgical operation that creates an opening from the colon to the surface of the body to function as an anus