Noun
An instrument used to measure variations in a magnetic field.
(aviation) A rate-of-climb indicator.
Synonym: (informal) vario
Also, nearly every glider contains an instrument known as a variometer (a very sensitive vertical speed indicator) which shows visually (and often audibly) the presence of lift and sink. Source: Internet
The variometer indicates climb rate or sink rate with audio signals (beeps) and/or a visual display. Source: Internet
A variometer is a very sensitive vertical speed indicator. Source: Internet