eudiometer
noun
eu·di·om·e·ter ˌyü-dē-ˈä-mə-tər 
: an instrument for the volumetric measurement and analysis of gases
eudiometric
ˌyü-dē-ə-ˈme-trik
adjective eudiometrically
ˌyü-dē-ə-ˈme-tri-k(ə-)lē
adverb 
Word History
Etymology
modification of Italian eudiometro, from Greek eudia fair weather (from eu- + -dia weather—akin to Latin dies day) + Italian -metro -meter, from Greek metron measure
First Known Use
1777, in the meaning defined above
Medical Definition
eudiometer
noun
eu·di·om·e·ter ˌyüd-ē-ˈäm-ət-ər
: an instrument for the volumetric measurement and analysis of gases