lens cover vs lens cap

lens cover and lens cap both are nouns.

Word	Noun	Adjective	Verb	Adverb
lens cover	Yes	No	No	No
lens cap	Yes	No	No	No

As nouns, lens cover and lens cap are synonyms defined as:

lens cover and lens cap: cap used to keep lens free of dust when not in use

lens cover (noun)	lens cap (noun)
cap used to keep lens free of dust when not in use	cap used to keep lens free of dust when not in use