travertine, n. [F. travertin, It. travertino, tiburtino, L. lapis Tiburtinus, fr. Tibur an ancient town of Latium, now Tivoli.].
A white concretionary form of calcium carbonate, usually hard and semicrystalline. It is deposited from the water of springs or streams holding lime in solution. Extensive deposits exist at Tivoli, near Rome. [1913 Webster]