external auditory canal vs ear canal

external auditory canal and ear canal both are nouns.

Word	Noun	Adjective	Verb	Adverb
external auditory canal	Yes	No	No	No
ear canal	Yes	No	No	No

As nouns, external auditory canal and ear canal are synonyms defined as:

external auditory canal and ear canal: either of the passages in the outer ear from the auricle to the tympanic membrane

Other synonyms of external auditory canal include acoustic meatus, auditory canal, auditory meatus.

external auditory canal (noun)	ear canal (noun)
either of the passages in the outer ear from the auricle to the tympanic membrane	either of the passages in the outer ear from the auricle to the tympanic membrane