- Sinuses
- 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.
[1913 Webster]
2. A bay of the sea; a recess in the shore. [1913 Webster]
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. [1913 Webster]
4. (Med.) A narrow, elongated cavity, in which pus is collected; an elongated abscess with only a small orifice. [1913 Webster]
5. (Bot.) A depression between adjoining lobes. [1913 Webster]
Note: A sinus may be rounded, as in the leaf of the white oak, or acute, as in that of the red maple. [1913 Webster]
{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. [1913 Webster]
The Collaborative International Dictionary of English. 2000.