I'so-cheim, n.
n. [Gr. ἴσος, equal, and χεῖμα, χειμών, winter.] (Phys. Geog.) An imaginary line connecting places on the earth having the same mean winter temperature.
n. [Gr. ἴσος, equal, and χεῖμα, χειμών, winter.] (Phys. Geog.) An imaginary line connecting places on the earth having the same mean winter temperature.