‖n. [ NL., fr. Gr. 'e`mmetros in measure, proportioned, suitable ('en in + me`tron measure) + 'w`ps, 'wpo`s, eye. ] (Med.) That refractive condition of the eye in which the rays of light are all brought accurately and without undue effort to a focus upon the retina; -- opposed to hypermetropia, myopia, and astigmatism. [ 1913 Webster ]