isopectic

[ ahy-suh-pek-tik ]
/ ˌaɪ səˈpɛk tɪk /

noun

a line drawn on a map connecting all points where ice starts to form at approximately the same period at the onset of winter.

Origin of isopectic

iso- + -pectic < Greek pēktikós freezing; see pectic
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019