Defn: A narrow, elongated cavity, in which pus is collected; an elongated abscess with only a small orifice.
5. (Bot.)
Defn: A depression between adjoining lobes.
Note: A sinus may be rounded, as in the leaf of the white oak, or acute, as in that of the red maple. Pallial sinus. (Zoöl.) See under Pallial. — Sinus venosus. Etym: [L., venous dilatation.] (Anat.) (a) The main part of the cavity of the right auricle of the heart in the higher vertebrates. (b) In the lower vertebrates, a distinct chamber of the heart formed by the union of the large systematic veins and opening into the auricle.
SINUSOID
Si"nus*oid, n. Etym: [Sinus + -oid.] (Geom.)
Defn: The curve whose ordinates are proportional to the sines of the abscissas, the equation of the curve being y = a sin x. It is also called the curve of sines.
SINUSOIDAL
Si`nus*oid"al, a. (Geom.)
Defn: Of or pertaining to a sinusoid; like a sinusoid.
SIOGOON
Sio"goon, n.
Defn: See Shogun.