noun ·Uncommon ·Advanced level

Definitions

Noun

1. 1
   The chemical element (symbol Ar) with an atomic number of 18. The third most abundant gas in the Earth's atmosphere, it is a colourless, odourless, inert noble gas. countable, uncountable
2. 2
   a colorless and odorless inert gas; one of the six inert gases; comprises approximately 1% of the earth's atmosphere wordnet
3. 3
   A single atom of this element. countable

Synonyms

All synonyms

ammoniaaratomic number 18carbon dioxidee938e938 when used as a packaging gas

Example

More examples

"Helium, neon, argon, krypton, xenon and radon are noble gases."

Etymology

From Ancient Greek ἀργός (argós, “idle, lazy”), because of its inertness, + -on, used for all noble gases.

Related phrases

argon chloride fluorideargon chloride hydrideargon fluoride hydrideargon fluorohydrideargon hydrofluorideargon-36argon-38argon-40meta-argonpotassium-argon datingatomic number

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.