hiatus (n.)
1560s, "break or opening" in a material object, especially in anatomy, from Latin hiatus "opening, aperture, rupture, gap," from past participle stem of hiare "to gape, stand open," from PIE root *ghai- "to yawn, gape" (see yawn (v.)). Sense of "gap or interruption in events, etc.;" "space from which something requisite to completeness is absent" [Century Dictionary] is recorded from 1610s.