record cover vs record sleeve

record cover and record sleeve both are nouns.

Word	Noun	Adjective	Verb	Adverb
record cover	Yes	No	No	No
record sleeve	Yes	No	No	No

As nouns, record cover and record sleeve are synonyms defined as:

record cover and record sleeve: a sleeve for storing a phonograph record

record cover (noun)	record sleeve (noun)
a sleeve for storing a phonograph record	a sleeve for storing a phonograph record