um

v. i. [ Umbe + cast. ] To cast about; to consider; to ponder. [ Obs. ] Sir T. Malory. [ 1913 Webster ]

n. [ L. umbella a little shadow, umbrella, dim. of umbra shade. See Umbrella. ] (Bot.) A kind of flower cluster in which the flower stalks radiate from a common point, as in the carrot and milkweed. It is simple or compound; in the latter case, each peduncle bears another little umbel, called umbellet, or umbellule. [ 1913 Webster ]

a. (Bot.) Of or pertaining to an umbel; having the form of an umbel. [ 1913 Webster ]

{ } a. [ NL. umbellatus. ] (Bot.) Bearing umbels; pertaining to an umbel; umbel-like; as, umbellate plants or flowers. [ 1913 Webster ]

n. (Bot.) A small or partial umbel; an umbellule. [ 1913 Webster ]

a. (Chem.) Pertaining to, or obtained from, certain umbelliferous plants; as, umbellic acid. [ 1913 Webster ]

Umbellic acid. (Chem.) (a) Anisic acid. [ Obs. ] (b) A yellow powder obtained from umbelliferone. [ 1913 Webster ]

n. [ NL. See Umbelliferous. ] (Bot.) A plant producing an umbel or umbels. [ 1913 Webster ]

n. (Chem.) A tasteless white crystalline substance, C9H6O3, found in the bark of a certain plant (Daphne Mezereum), and also obtained by the distillation of certain gums from the Umbelliferae, as galbanum, asafetida, etc. It is analogous to coumarin. Called also hydroxy-coumarin. Its strong fluorescence under ultraviolet light makes it useful in analytical biochemistry, as, for example, to detect phosphatase activity by hydrolysis of umbelliferyl phosphate. [ 1913 Webster +PJC ]