Hiatus \Hi*a"tus\, n.; pl. L. {Hiatus}, E. {Hiatuses}. [L., fr. hiare, hiatum, to gape; akin to E. yawn. See {Yawn}.] 1. An opening; an aperture; a gap; a chasm; esp., a defect in a manuscript, where some part is lost or effaced; a space where something is wanting; a break. 2. (Gram.) The concurrence of two vowels in two successive words or syllables. --Pope.