isopor

[ ahy-suh-pawr ]
/ ˈaɪ səˌpɔr /

noun

an imaginary line on the earth's surface connecting points of equal annual change in the declination, inclination, or other components of the earth's magnetic field.

Origin of isopor

1930–35; iso- + -por < Greek póros path, pore2
Also called isoporic line.

Related forms

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