ARGON

ar·gon   (är'gŏn')    n.   Symbol Ar A colorless, odorless, inert gaseous element constituting approximately one percent of Earth's atmosphere, from which it is commercially obtained by fractionation for use in electric light bulbs, fluorescent tubes, and radio vacuum 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. See Table at element. [From Greek ārgon, neuter of ārgos, idle, inert : a-, without; see a-1 + ergon, work; see werg- in Indo-European roots.]

argon 

Main Entry: ar·gon
Pronunciation: 'är-"gän
Function: noun
: a colorless odorless inert gaseous element found in the air and in volcanicgases and used especially as a filler for electric bulbs —symbol Ar; —see ELEMENT table

argon ar·gon (är'gŏn')
n.
Symbol Ar
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.

argon   (är'gŏn')  Pronunciation Key  Symbol Ar 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.