1.Relating to equality of temperature, or an isotherm.
2.(Phys. Geog.) Having reference to the geographical distribution of temperature, as exhibited by means of isotherms; as, an isothermal line; an isothermal chart.
Isothermal line. (b)A line drawn on a diagram of energy such that its ordinates represent the pressures of a substance corresponding to various volumes, while the absolute temperature is maintained at a constant value.
