Sinus

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

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.