Lithocyst \Lith"o*cyst\ (l[i^]th"[-o]*s[i^]st), n. [Litho- +
cyst.] (Zool.)
A sac containing small, calcareous concretions (otoliths).
They are found in many Medus[ae], and other invertebrates,
and are supposed to be auditory organs.
[1913 Webster]