n. A drop; specifically, in architecture, one of a series of pendent ornaments, generally in the form of the frustum of a cone, but sometimes cylindrical, attached to the under side of the mutules and regulæ of the Doric entablature.n. In pharmacy, a drop: usually, and in prescriptions, written gt., plural gtt.n. In zoology, a small spot, generally of a round or oval form, and not differing much in shade from the ground-color, as if made by a drop of water; any small color-spot, especially when guttiform.n. Same as guttapercha.n. A colorless pulverulent compound, C10H16, contained in gutta-percha. It begins to melt at 180° C., and loses its flexibility on exposure to air and light.