The Collaborative International Dictionary of English v.0.48:

Infundibulum \In`fun*dib"u*lum\, n.; pl. L. Infundibula, E.
   Infundibulums. [L., a funnel, from infundere to pour in or
   into. See Infuse.]
   1. (Anat.) A funnel-shaped or dilated organ or part; as, the
      infundibulum of the brain, a hollow, conical process,
      connecting the floor of the third ventricle with the
      pituitary body; the infundibula of the lungs, the enlarged
      terminations of the bronchial tubes.
      [1913 Webster]

   2. (Zool.)
      (a) A central cavity in the Ctenophora, into which the
          gastric sac leads.
      (b) The siphon of Cephalopoda. See Cephalopoda.
          [1913 Webster]

WordNet (r) 3.0 (2006):

infundibulum
    n 1: any of various funnel-shaped parts of the body (but
         especially the hypophyseal stalk)