skin patch vs transdermal patch

skin patch and transdermal patch both are nouns.

Word	Noun	Adjective	Verb	Adverb
skin patch	Yes	No	No	No
transdermal patch	Yes	No	No	No

As nouns, skin patch and transdermal patch are synonyms defined as:

skin patch and transdermal patch: a medicated adhesive pad placed on the skin for absorption of a time released dose of medication into the bloodstream

skin patch (noun)	transdermal patch (noun)
a medicated adhesive pad placed on the skin for absorption of a time released dose of medication into the bloodstream	a medicated adhesive pad placed on the skin for absorption of a time released dose of medication into the bloodstream