- Breathing hole - The nostril, or one of the nostrils, of whales,
porpoises, and allied animals. - One of the external openings communicating with the air
tubes or tracheae of insects, myriapods, and arachnids. They are
variable in number, and are usually situated on the sides of the thorax
and abdomen, a pair to a segment. These openings are usually
elliptical, and capable of being closed. See Illust. under Coleoptera. - A tubular orifice communicating with the gill cavity of
certain ganoid and all elasmobranch fishes. It is the modified first
gill cleft. - Any small aperture or vent for air or other fluid.
- Main tree trunk - Tree trunk - The trunk or stem of a tree, or that which is like it. - An aperture, with a wooden shutter, in the wall of a house,
for giving, occasionally, air or light; also, a small closet. - A measure. See Boll, n., 2. - Any one of several varieties of friable earthy clay, usually
colored more or less strongly red by oxide of iron, and used to color
and adulterate various substances. It was formerly used in medicine. It
is composed essentially of hydrous silicates of alumina, or more rarely
of magnesia. See Clay, and Terra alba. - A bolus; a dose.