One nine-letter word relating to the ear is "auditory."
Auricular means related to the external ear.
audiology
One ten-letter word relating to the ear is "otologist," which is a medical specialist who deals with the diagnosis and treatment of ear disorders.
Lobe
sound
otic
otological
vertigo
E A R
otic
OTIC
otic
otic
The Latin word auris (from which we get the word aural relating to the ear) which combined with the Old English ēare, Dutch oor and German Ohr have all contributed to our use of the word ear.