rug vs floor cover

rug and floor cover both are nouns.

Word	Noun	Adjective	Verb	Adverb
rug	Yes	No	No	No
floor cover	Yes	No	No	No

As nouns, floor cover is a hypernym of rug; that is, floor cover is a word with a broader meaning than rug:

rug: floor covering consisting of a piece of thick heavy fabric (usually with nap or pile)
floor cover: a covering for a floor

Other hypernyms of rug include floor covering, furnishing.

rug (noun)	floor cover (noun)
floor covering consisting of a piece of thick heavy fabric (usually with nap or pile)	a covering for a floor