hard coal vs anthracite coal

hard coal and anthracite coal both are nouns.

Word	Noun	Adjective	Verb	Adverb
hard coal	Yes	No	No	No
anthracite coal	Yes	No	No	No

As nouns, hard coal and anthracite coal are synonyms defined as:

hard coal and anthracite coal: a hard natural coal that burns slowly and gives intense heat

Other synonyms of hard coal include anthracite.

hard coal (noun)	anthracite coal (noun)
a hard natural coal that burns slowly and gives intense heat	a hard natural coal that burns slowly and gives intense heat