HIA'TUS, noun [Latin from hio, to open or gape.] 1. An opening; an aperture; a gap; a chasm. 2. The opening of the mouth in reading or speaking, when a word ends with a vowel, and the following word begins with a vowel. 3. A defect; a chasm in a manuscript, where some part is lost or effaced.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI