D defs.my
Entry 1 sense Webster, 1913

Limestone

/(līm"stōn`)/ · Lime·stone · IPA /ˈlaɪmˌstoʊn/
01 n. A rock consisting chiefly of calcium carbonate or carbonate of lime. It sometimes contains also magnesium carbonate, and is then called mag…
  1. 1.
    A rock consisting chiefly of calcium carbonate or carbonate of lime. It sometimes contains also magnesium carbonate, and is then called magnesian or dolomitic limestone. Crystalline limestone is called marble.