infundibulum /in′fundib″yələm/ pl. infundibula [L, funnel] , a funnel-shaped structure or passage, such as the cavity formed by the fimbriae tubae at the distal end of the fallopian tubes, the stalk that extends from the hypothalamus to the posterior lobe of the pituitary gland, or the passage connecting the middle meatus of the nose with the frontal sinus.