Atom

How to spell atom

4 letters · 2 syllables

How to pronounce atom

Say the part in capitals loudest.

What does atom mean?

1. nounThe smallest unit of a chemical element, consisting of a nucleus surrounded by electrons.

Atom in a sentence

• A single atom of carbon bonds with four other particles.

• The chemistry teacher drew a hydrogen atom on the whiteboard.

Where does atom come from?

Language of origin: Greek

The word comes from the Greek atomos, which literally meant 'uncuttable' or 'that which cannot be divided', built from the negative prefix a- meaning 'not' and the root temnein meaning 'to cut'. Ancient Greek philosophers such as Democritus used it for the smallest possible particle of matter, the point at which cutting must stop. The word passed through Latin atomus and into English in the fifteenth century, keeping its sense of the tiniest indivisible unit. Ironically, twentieth-century physics showed the atom is in fact made of smaller parts, so the 'uncuttable' name survived even after splitting it became possible. The same temnein root for cutting also sits inside surgical terms like 'appendectomy' and 'anatomy', a useful reminder that the word is built from a clean, simple two-part shape.

How the word is built

• a- (Greek: not)
• tom (cut, from temnein 'to cut') = 'uncuttable'