type slug vs type metal

type slug and type metal both are nouns.

Word	Noun	Adjective	Verb	Adverb
type slug	Yes	No	No	No
type metal	Yes	No	No	No

As nouns, type metal is a hypernym of type slug; that is, type metal is a word with a broader meaning than type slug:

type slug: a strip of type metal used for spacing
type metal: an alloy of tin and lead and antimony used to make printing type

type slug (noun)	type metal (noun)
a strip of type metal used for spacing	an alloy of tin and lead and antimony used to make printing type