1. (n.) A kind of oven, or reverberatory furnace, used for the calcination of sand and potash, and converting them into frit.

2. (n.) A hollow tube or spur at the base of a petal or corolla.

3. (n.) A slender bony process from the ankle joint of bats, which helps to support the posterior part of the web, in flight.

4. (n.) A spur, or spurlike prominence.

5. (n.) A curved ridge in the floor of the leteral ventricle of the brain; the calcar avis, hippocampus minor, or ergot.