1. A funnel-shaped opening, passage, or structure in vertebrates; such as, the stalk connecting the pituitary gland to the brain or the opening of a fallopian tube into the ovary.
2. A funnel-shaped or dilated organ or part; such 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.
3. The cone like upper anterior angle at the right cardiac ventricle from which the pulmonary artery arises.