NOUN (2)

1. a small round soft mass (as of chewed food);

2. a large pill; used especially in veterinary medicine;

The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "bolus":
   ball, balloon, bite, bladder, blob, boll, bubble, bulb, bulbil,
   bulblet, capsule, champ, chaw, chew, chomp, cud, ellipsoid, geoid,
   globe, globelet, globoid, globule, glomerulus, gnash, gob, gobbet,
   knob, knot, lozenge, morsel, mouthful, munch, nibble, nip,
   oblate spheroid, orb, orbit, orblet, pellet, pill,
   prolate spheroid, quid, rondure, snap, sphere, spheroid, spherule,
   swallow, tablet, troche