Calcar

·noun A spur, or spurlike prominence.

II. Calcar ·noun A hollow tube or spur at the base of a petal or corolla.

III. Calcar ·noun A curved ridge in the floor of the leteral ventricle of the brain; the calcar avis, hippocampus minor, or ergot.

IV. Calcar ·noun A slender bony process from the ankle joint of bats, which helps to support the posterior part of the web, in flight.

V. Calcar ·noun A kind of oven, or reverberatory furnace, used for the calcination of sand and potash, and converting them into frit.