isabnormal

[ahy-sab-nawr-muh l]

noun Meteorology.

a line on a map or chart connecting points having an equal deviation from the normal value of some meteorological quantity, as temperature.

Also isoabnormal.

Compare isanomal.

Origin of isabnormal

First recorded in 1850–55; is- + abnormal

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018