[mea.sles] n pl but sing or pl in constr [ME meseles, pl. of mesel measles, spot characteristic of measles; akin to MD masel spot characteristic of measles] (14c) 1 a: an acute contagious viral disease marked by an eruption of distinct red circular spots b: any of various eruptive diseases (as German measles)
2. [ME mesel infested with tapeworms, lit., leprous, fr. OF, fr. ML misellus leper, fr. L, wretch, fr. misellus, dim. of miser miserable]: infestation with or disease caused by larval tapeworms in the muscles and tissues