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 clastic sedimentary rock formed from fragments of other rocks, fossils and grains. The stone is predominantly composed of calcite and can be various colours including white, grey and pink. The appearance and workability of Limestone allows it to be used for diverse purposes, from decorative statues to exterior facades of buildings.