noun the siphon of cephalopoda. ·see cephalopoda.
2. infundibulum ·noun a central cavity in the ctenophora, into which the gastric sac leads.
3. infundibulum ·noun 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.