ATOMIC NUMBER 21

 Dictionary entry overview: What does atomic number 21 mean? 

• ATOMIC NUMBER 21 (noun)
  The noun ATOMIC NUMBER 21 has 1 sense:

1. a white trivalent metallic element; sometimes classified in the rare earth group; occurs in the Scandinavian mineral thortveitite

  Familiarity information: ATOMIC NUMBER 21 used as a noun is very rare.

 Dictionary entry details 

• ATOMIC NUMBER 21 (noun)

Sense 1

Meaning:

A white trivalent metallic element; sometimes classified in the rare earth group; occurs in the Scandinavian mineral thortveitite

Classified under:

Nouns denoting substances

Synonyms:

atomic number 21; Sc; scandium

Hypernyms ("atomic number 21" is a kind of...):

metal; metallic element (any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.)

Holonyms ("atomic number 21" is a substance of...):

thortveitite (a mineral consisting of scandium yttrium silicate; a source of scandium)