IPA: //ˈɛrəˌmɛtər//
KK: /ˈɛrəmətər/
A device used to measure the weight and density of air or other gases.
The scientist used an aerometer to measure the density of the air in the laboratory.
Aerometer → It is formed from "aero-" (from Greek "aēr", meaning air) and "-meter" (from Greek "metron", meaning measure). The word "aerometer" refers to an instrument that measures the density or pressure of air.
Think of 'air' ('aero-') being 'measured' ('-meter') — that's what an aerometer does.