horny layer vs corneum

horny layer and corneum both are nouns.

Word	Noun	Adjective	Verb	Adverb
horny layer	Yes	No	No	No
corneum	Yes	No	No	No

As nouns, horny layer and corneum are synonyms defined as:

horny layer and corneum: the outermost layer of the epidermis consisting of dead cells that slough off

Other synonyms of horny layer include stratum corneum.

horny layer (noun)	corneum (noun)
the outermost layer of the epidermis consisting of dead cells that slough off	the outermost layer of the epidermis consisting of dead cells that slough off