n. A contagious disease of man, with an incubation period of about nine or ten days, and a period of invasion of about three or four days, in which there are pyrexia and rapid pulse, inflammation of the mucous membrane of the eyes and upper air-passages, and bronchitis, followed by an eruption of small rose-colored papulæ, which arrange themselves in curvilinear forms.n. An old name for several diseases of swine or sheep, caused by the scolex or measle of a tapeworm, and characterized by reddish watery pustules on the skin, cough, feverishness, and discharge at the nostrils.—3. A disease of plants; any blight of leaves appearing in spots, whether due to the attacks of insects or to the action of weather. See measle, 1.n. See measle. 2.n. In photography, a defect in silver-printing consisting in semi-opaque blotches caused by imperfect fixation by the insoluble silver hyposulphite visible when the prints are held to the light. In time these spots become yellow.n. Same as scarlet fever.