variometer
/ˌvɛriˈɑmɪtər/
noun
- An instrument used to measure variations in a magnetic field, especially in geophysics or aviation.
- The geophysicist used a variometer to detect small changes in the Earth's magnetic field.
- The research team deployed a variometer near the volcano to monitor magnetic anomalies.
- Pilots rely on a variometer to know whether the aircraft is climbing or descending.
Synonyms