n. A sharp excrescence on a plant: usually a branch, or the termination of a stem or branch, indurated, leafless, and attenuated to a point; a spine; a prickle. See spine, 1.n. Figuratively, that which wounds or annoys; a cause of discomfort or irritation; a painful circumstance.n. One of numerous thorny shrubs or trees, especially the members of the genus Cratægus, otherwise called haw.n. In zoology, some sharp process, horn, or spine. See spine, 3.n. In entomology, one of certain geometrid moths: an English book-name. The little thorn is Epione advenaria; the early thorn is Selenia illunaria.n. In lace-making, a small pointed projection used to decorate the cordon-net, etc. Compare spine, 5.n. The Anglo-Saxon letter þ, equivalent to th; also, the corresponding character in Icelandic.n. In the United States, sometimes, the scarlet-fruited thorn.n. See Macrocnemum.To prick or pierce with or as with a thorn.To fasten with a thorn.Supplied (?).To be supplied (?).