Meaning of gradiometer

gra•di•om•e•ter

Pronunciation: (grā"dē-om'i-tur), [key]
— n. Physics.
  1. any instrument used to measure a gradient, as the rate of change of the geomagnetic field. Cf. gradient (def. 3a).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.