\bóilz-\ [Robert Boyle] np (ca. 1860) The part of the ideal-gas law, due to Robert Boyle, stating that the volume of a gas is inversely proportional to its pressure. This can also be stated as, at a constant temperature the volume of a given quantity of any gas varies inversely as the pressure to which the gas is subjected. For a perfect gas, changing from pressure p and volume v to pressure p′ and volume v′ without change of temperature, pv = p′ v′. (Atkins PW, De Paula J (2001) Physical chemistry, 7th edn.WH Freeman Co., New York).