/ahr"gon/ , n. Chem.
a colorless, odorless, chemically inactive, monatomic, gaseous element that, because of its inertness, is used for filling fluorescent and incandescent lamps and vacuum tubes. Symbol: Ar; at. no.: 18; at. wt.: 39.948.
[ 1890-95; argós inactive, not working, idle, contr. of aergós equiv. to a- A- 6 + érg ( on ) work + -os adj. suffix ]