Source : Webster's Revised Unabridged Dictionary (1913)

Bolus \Bo"lus\, n.; pl. {Boluses}. [L. bolus bit, morsel; cf. G.
   ? lump of earth. See {Bole}, n., clay.]
   A rounded mass of anything, esp. a large pill.

Source : WordNet®

bolus
     n 1: a small round soft mass (as of chewed food)
     2: a large pill; used especially in veterinary medicine