Lewis & Short

2. ū̆trĭcŭlus, i, m. dim. [uterus].

  1. I. Lit., in gen., the belly, abdomen, of bees, Plin. 11, 12, 12, § 31.
    1. B. Esp., a little womb or matrix, Plin. 11, 37, 84, § 209; 30, 14, 43, § 124.
  2. II. Transf., of plants, a bud or calycle of a flower, a hull or husk of grain, Plin. 16, 25, 39, § 94; 18, 11, 29, § 115.