auricle vs pinna

auricle and pinna both are nouns.

Word	Noun	Adjective	Verb	Adverb
auricle	Yes	No	No	No
pinna	Yes	No	No	No

As nouns, auricle and pinna are synonyms defined as:

auricle and pinna: the externally visible cartilaginous structure of the external ear

Other synonyms of auricle include ear.

auricle (noun)	pinna (noun)
a small conical pouch projecting from the upper anterior part of each atrium of the heart	the externally visible cartilaginous structure of the external ear
the externally visible cartilaginous structure of the external ear	division of a usually pinnately divided leaf