limestone

Etymology

From lime + stone.

noun

1. An abundant rock of marine and fresh-water sediments; primarily composed of calcite (CaCO₃); it occurs in a variety of forms, both crystalline and amorphous.
   As each blast furnace uses 200 tons of limestone daily, and each limestone kiln 150 tons, a total of 730 tons of limestone has to be carried daily, in addition to limestone chippings, which are sold. 1939 July, “What the Railways are Doing: The New Ebbw Vale Steelworks”, in Railway Magazine, page 68
2. (attributive) Pertaining to or made of limestone.
   a limestone viaduct