Source : Webster's Revised Unabridged Dictionary (1913)

Sacculus \Sac"cu*lus\, n.; pl. {Sacculi}. [L., little sack.]
   (Anat.)
   A little sac; esp., a part of the membranous labyrinth of the
   ear. See the Note under {Ear}.

Source : WordNet®

sacculus
     n : a small sac or pouch (especially the smaller chamber of the
         membranous labyrinth) [syn: {saccule}]