Definition of geobarometer in US English:

geobarometer

noun

Geology
  • A mineral or mineral assemblage whose chemical composition or stability range is sensitive to pressure, so it may be used as a guide to the pressure under which the rock containing it was formed.

Origin

1920s (in an earlier sense). From geo- + barometer.

Pronunciation

geobarometer

/ˌdʒiːə(ʊ)bəˈrɒmɪtə/