Mathematics. ( 1 of a topology or topological space) having the property that every subset is an open set. 2  defined only for an isolated set of points: a discrete variable. 3  using only arithmetic and algebra; not involving calculus: discrete methods.
limestone - a sedimentary rock consisting mainly of calcium that was deposited by the remains of marine animals. atomic number 20, Ca, calcium - a white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals.
Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO 3) in the form of the mineral calcite. It most commonly forms in clear, warm, shallow marine waters.It is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal and fecal debris.imestone is a sedimentary rock composed primarily of calcium carbonate (CaCO 3) in the form of the mineral calcite. It most commonly forms in clear, warm, shallow marine waters.