pearlite vs cast iron

pearlite and cast iron both are nouns.

Word	Noun	Adjective	Verb	Adverb
pearlite	Yes	No	No	No
cast iron	Yes	No	No	No

pearlite (noun)	cast iron (noun)
a lamellar mixture of cementite and ferrite formed during the cooling of austenite; a constituent of steel and cast iron	an alloy of iron containing so much carbon that it is brittle and so cannot be wrought but must be shaped by casting