Calcar

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.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.