isochasm

[ ahy-suh-kaz-uh m ]
/ ˈaɪ səˌkæz əm /

noun Meteorology.

a line on a map or chart connecting points where auroras are observed with equal frequency.

Origin of isochasm

First recorded in 1880–85; iso- + chasm

Related forms

i·so·chas·mic, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019