Meaning

verb become wider

verb cause to expand as it by internal pressure

verb swell from or as if from internal pressure

originEtymology tree Proto-Indo-European *dwóh₁ Proto-Indo-European *d(w)is- Proto-Italic *dis- Latin dis- Proto-Indo-European *ten- Proto-Indo-European *tend-der. Proto-Italic *tendō Latin tendō Latin distendōbor. English distend Borrowed from Latin distendō.

Etymology from Wiktionary, CC BY-SA 3.0