Otocyst \O"to*cyst\, n. [Oto- + cyst.] (Zool. & Anat.)
An auditory cyst or vesicle; one of the simple auditory
organs of many invertebrates, containing a fluid and
otoliths; also, the embryonic vesicle from which the parts of
the internal ear of vertebrates are developed.
[1913 Webster]