Having constant temperature.

1816, literally "of equal heat," from French isotherme (see isotherm) + -al (1). As a noun, "isothermal line," from 1849.

adj. Having or marking equality of temperature.

A system condition in which the temperature remains constant. This implies that temperature increases and decreases are compensated by sufficient heat exchange with the environment of the system.

Pertaining to changes or other phenomena occurring at a constant temperature.

(adj) of a process or change taking place at constant temperature

Of or indicating equality of temperature.

Of equal or constant temperature with respect to either space or time.

Of constant temperature (e.g., an isothermal air jet has the same temperature as the surrounding air).

Of equal or constant temperature, with respect to either space or time; more commonly, temperature with height; a zero lapse rate.

Being at constant temperature.

Changes of volume or pressure under conditions of constant temperature.

A process that is kept at a constant temperature.