name, noun ·Uncommon ·Advanced level

Definitions

Noun

1. 1
   The chemical element (symbol Kr) with an atomic number of 36. It is a colourless, odourless noble gas that only reacts with fluorine. It is one of the rarest gases in the Earth's atmosphere. uncountable
2. 2
   a colorless element that is one of the six inert gasses; occurs in trace amounts in air wordnet
3. 3
   An atom of this element. countable

Proper Noun

1. 1
   A fictional planet, the native world of Superman, named after the element krypton.

Synonyms

All synonyms

ammoniaatomic number 36carbon dioxidegaskrnitrogen

Example

More examples

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

Etymology

From Ancient Greek κρυπτός (kruptós, “hidden”) + -on, used for all noble gases.

Related phrases

krypton difluoridekrypton fluoridekrypton-85atomic numbernoble gas

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