Emily Dickinson Lexicon

VALVE, n. [valv; L. valvæ, folding doors; coinciding with volvo.]

1. A folding door. Swift through the valves the visionary fair / Repass'd. – Pope.
2. A lid or cover so formed as to open a communication one direction, and close it in the other. Thus the valve of a common pump opens upward to admit the water, and closes downward to prevent its return.
3. In anatomy, a membranous partition within the cavity of a vessel, which opens to allow the passage of a fluid in one direction, and shuts to prevent its regurgitation. – Parr.
4. In botany, the outer coat, shell, or covering of a capsule or other pericarp, or rather one of the pieces which compose it; also, one of the leaflets composing the calyx and corol in grasses. – Martyn.
5. One of the pieces or divisions in bivalve and multivalve shells. – Ed. Encyc.