gradiometer

[ grey-dee-om-i-ter ]
/ ˌgreɪ diˈɒm ɪ tər /

noun Physics.

any instrument used to measure a gradient, as the rate of change of the geomagnetic field. Compare gradient(def 3a).

Origin of gradiometer

First recorded in 1800–10; gradi(ent) + -o- + -meter

British Dictionary definitions for gradiometer

gradiometer
/ (ˌɡrædɪˈɒmɪtə) /

noun

physics an instrument for measuring the gradient of a magnetic field
surveying an instrument used to ensure that a long gradient remains constant