isocryme means an isoline connecting points on the Earth's surface having the same mean temperature in the coldest month of the year. Lexicurio rates it Sui generis — a strength score of 87 out of 100.
Etymology
From iso- + Ancient Greek κρυμός (krumós, “cold, chilliness”) (see κρύος (krúos)). Coined by James D. Dana in 1854, who glossed κρυμός as "extreme cold".
noun
- An isoline connecting points on the Earth's surface having the same mean temperature in the coldest month of the year.