iso·bar·ic \| ̷ ̷ ̷ ̷ at iso-+|barik\adjective Etymology: International Scientific Vocabulary isobar + -ic 1.: showing equal pressure: as a.: showing points in the atmosphere having equal barometric pressure < isobaric lines > b.: taking place without change of pressure < isobaric expansion > < isobaric process > 2.: of, relating to, or having the relationship of an isobar