湾, 穴, 窦, 窦房结, 窦道, 鼻窦, 瘘, 瘘管

Sinus \Si"nus\, n.; pl. L. {Sinus}, E. {Sinuses}. [L., a bent
surface, a curve, the folds or bosom of a garment, etc., a
bay. Cf. {Sine}, n.]
1. An opening; a hollow; a bending.

2. A bay of the sea; a recess in the shore.

3. (Anat. & Zo["o]l.) A cavity; a depression. Specifically:
(a) A cavity in a bone or other part, either closed or
with a narrow opening.
(b) A dilated vessel or canal.

4. (Med.) A narrow, elongated cavity, in which pus is
collected; an elongated abscess with only a small orifice.

5. (Bot.) 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}. (Zo["o]l.) See under {Pallial}.

{Sinus venosus}. [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.