- keyAn object designed to open and close a lock or to activate or deactivate something, especially a length of metal inserted into a narrow opening on the lock to which it is matched (keyed).
- cayA small, low island largely made of sand or coral.
- cayoA small island or ledge of rock in the water; a key.
- key limeA small yellow (when ripe, usually sold green) lime, of hybrid Citrus × aurantiifolia, especially those from southern Florida.