lip vs external body part

lip and external body part both are nouns.

Word	Noun	Adjective	Verb	Adverb
lip	Yes	No	No	No
external body part	Yes	No	No	No

As nouns, external body part is a hypernym of lip; that is, external body part is a word with a broader meaning than lip:

lip: either of two fleshy folds of tissue that surround the mouth and play a role in speaking
external body part: any body part visible externally

Other hypernyms of lip include articulator.

lip (noun)	external body part (noun)
either the outer margin or the inner margin of the aperture of a gastropod's shell	any body part visible externally
the top edge of a vessel or other container
either of two fleshy folds of tissue that surround the mouth and play a role in speaking
an impudent or insolent rejoinder
(botany) either of the two parts of a bilabiate corolla or calyx