(1):

(a.) Having the form or structure of a vesicle; as, a vesicular body.

(2):

(a.) Containing, or composed of, vesicles or vesiclelike structures; covered with vesicles or bladders; vesiculate; as, vesicular coral; vesicular lava; a vesicular leaf.

(3):

(a.) Of or pertaining to vesicles; esp., of or pertaining to the air vesicles, or air cells, of the lungs; as, vesicular breathing, or normal breathing, in which the air enters freely the air vesicles of the lungs.