Possible Definitions:
1. Sinus (pl. ) of Sinus
2. Sinus (n.) An opening; a hollow; a bending.
3. Sinus (n.) A bay of the sea; a recess in the shore.
4. Sinus (n.) A cavity; a depression.
5. Sinus (n.) A cavity in a bone or other part, either closed or with a narrow opening.
6. Sinus (n.) A dilated vessel or canal.
7. Sinus (n.) A narrow, elongated cavity, in which pus is collected; an elongated abscess with only a small orifice.
8. Sinus (n.) A depression between adjoining lobes.