absorptiometer

noun

ab·​sorp·​ti·​om·​e·​ter əb-ˌsȯrp-shē-ˈäm-ət-ər  -ˌzȯrp- 

-tē-ˈäm-

1

: an instrument for measuring the reduction of pressure in a gas as it is absorbed by a liquid to determine the absorption rate

2

: a colorimeter for transparent fluids usually employing photoelectric means of comparison

absorptiometric

-shē-ō-ˈme-trik, -tē- 

adjective