argon ar·gon (är'gŏn')
A colorless, inert gaseous element constituting [approx] one percent of Earth's atmosphere, used in electric bulbs and fluorescent tubes and as an inert gas shield in arc welding. Atomic number 18; atomic weight 39.948; melting point -189.3°C; boiling point -185.9°C.
A colorless, odorless element in the noble gas group. Argon makes up about one percent of the atmosphere. It is used in electric light bulbs, fluorescent tubes, and radio vacuum tubes. Atomic number 18; atomic weight 39.948; melting point -189.2°C; boiling point -185.7°C. See Periodic Table.