Pronunciation: (i-pis'tu-sis), [key]
—pl. -sesPronunciation: (-sēz"). [key]
1. Genetics.a form of interaction between nonallelic genes in which one combination of such genes has a dominant effect over other combinations.
a. the stoppage of a secretion or discharge.
b. a scum that forms on a urine specimen upon standing.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.