Main Entry: Gei·ger counter

Pronunciation: \ˈgī-gər-\

Function: noun

Etymology: Hans Geiger †1945 German physicist

Date: 1924

: an instrument for detecting the presence and intensity of radiations (as cosmic rays or particles from a radioactive substance) by means of their ionizing effect on an enclosed gas which results in a pulse that is amplified and fed to a device giving a visible or audible indication