Isothermal

a.
  1. Relating to equality of temperature, or an isotherm.
    2. Isothermal line
    1. An isotherm
    2. 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.
    Isothermal zones ,
    spaces on opposite sides of the equator having the same mean temperature, and bounded by corresponding isothermal lines.