Emily Dickinson Lexicon

CON'CAVE, a. [L. concavus; con and cavus, hollow. See Cave.]

1. Hollow, and arched or rounded, as the inner surface of a spherical body; opposed to convex; as, a concave glass.
2. Hollow, in a general sense; as the concave shores of the Tiber. – Shak.
3. In botany, a concave leaf is one whose edge stands above the disk. – Martyn.