Sinus

Definition:

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

Compare sinus with other words:

minus vs. sinus