n. In prosody: Originally, the metrically unaccented part of a foot, as opposed to the thesis or part which receives the ictus or metrical stress.n. In prevalent modern usage, that part of a foot which bears the ictus or metrical accent, as opposed to the metrically unaccented part, called the thesis.n. In physiol. acoustics, a periodical increase in the intensity of a sound, producing a rhythmical effect.