n. In anc. orthoëpy and prosody: Pronunciation of a vowel as short.n. The shortening of a vowel or syllable, especially of one usually treated as a long; correption: opposed to diastole or ectasis.n. In physiology, the contraction of the heart and arteries for propelling the blood and thus carrying on the circulation.n. The contraction of the pulsatile vesicles of infusorians and other protozoans.n. [capitalized] In entomology, a genus of hymenopterous insects.