2 entries under this word
a. [Gr. ἴσος, equal, and θέρος, summer, from θέρειν, to make or become warm.] Having the nature of an isothere; indicating the distribution of temperature by means of an isothere; as, an isothermal chart.
Isothermal lines, lines passing through places having the same mean summer temperature.
a. [Fr. isotherme, from Gr. ἴσος, equal, and θέρμη, θερμόν, heat, fr. θερμός, hot. See supra.] Having reference to the geographical distribution of temperature, as exhibited by means of isotherms; as, the isothermal relations of different continents; having the nature of an isotherm; as, an isothermal line; illustrating the distribution of temperature by means of a series of isotherms; as, an isothermal chart.
Isothermal line. (a.) A line passing through places of equal mean temperature. (b.) (Thermodynamics.) 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.