iso·chor \ˈ ̷ ̷ ̷ ̷ˌkȯ(ə)r\noun alsoiso·chore\-ˌkō(ə)r\ (-s) Etymology: International Scientific Vocabulary is- + -chor (from Greek chōros place, clear space) — more at chor- : a line representing the variation of pressure with temperature when the volume of the substance operated on is constant • iso·chor·ic\| ̷ ̷ ̷ ̷|kȯrik, -|kōr-\adjective