canister vs case shot

canister and case shot both are nouns.

Word	Noun	Adjective	Verb	Adverb
canister	Yes	No	No	No
case shot	Yes	No	No	No

As nouns, canister and case shot are synonyms defined as:

canister and case shot: a metallic cylinder packed with shot and used as ammunition in a firearm

Other synonyms of canister include canister shot.

canister (noun)	case shot (noun)
metal container for storing dry foods such as tea or flour	a metallic cylinder packed with shot and used as ammunition in a firearm
a metallic cylinder packed with shot and used as ammunition in a firearm