Emily Dickinson Lexicon

SI'NUS, n. [L. a bay.]

1. A bay of the sea; a recess in seashore, shore, or an opening into the land. – Burnet.
2. In anatomy, a cavity in a bone or other part, wider at the bottom than at the entrance. – Encyc.
3. In surgery, a little elongated cavity, in which pus is collected; an elongated abscess with only a small orifice. – Encyc. Parr.
4. An opening; a hollow.