(1):
(n.) The minute breathing pores of leaves or other organs opening into the intercellular spaces, and usually bordered by two contractile cells.
(2):
(n.) One of the minute apertures between the cells in many serous membranes.
(3):
(n.) The line of dehiscence of the sporangium of a fern. It is usually marked by two transversely elongated cells. See Illust. of Sporangium.
(4):
(n.) A stigma. See Stigma, n., 6 (a) & (b).