floor covering vs rug

floor covering and rug both are nouns.

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

As nouns, rug is a hyponym of floor covering; that is, rug is a word with a more specific, narrower meaning than floor covering:

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

Other hyponyms of floor covering include mat, parqueterie, parquetry, carpet, carpeting.

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