declinometer

noun

instrument for measuring the variation of the magnetic needle

Wiktionary

Pronunciation: /ˌdɛklɪˈnɒmətə(ɹ)/

noun

Etymology: Etymology tree English decline Ancient Greek -ο- (-o-)der. Latin -o-bor. English -o- Proto-Indo-European *meh₁- Proto-Indo-European *-trom Proto-Hellenic *-tron Ancient Greek -τρον (-tron) Ancient Greek μέτρον (métron)der. English -meter English declinometer From decline + -o- + -meter.

An instrument for measuring magnetic declination.