lens cap vs lens cover

lens cap and lens cover both are nouns.

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

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

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

lens cap (noun)	lens cover (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