ear canal vs external auditory canal

ear canal and external auditory canal both are nouns.

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

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

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

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

ear canal (noun)	external auditory 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