# atom

> English word · Noun · IPA /ˈætəm/ · frequency rank #10,813

## Definitions
1. The smallest possible amount of matter which still retains its identity as a chemical element, now known to consist of a nucleus surrounded by electrons.
2. A hypothetical particle posited by Greek philosophers as an ultimate and indivisible component of matter.
3. The smallest, indivisible constituent part or unit of something.
4. In logical atomism, a fundamental fact that cannot be further broken down.
5. The smallest medieval unit of time, equal to fifteen ninety-fourths of a second.
6. A mote of dust in a sunbeam.
7. A very small amount; a whit.
8. An individual number or symbol, as opposed to a list; a scalar value.
9. An integer representing a particular string.
10. A non-zero member of a partially ordered set that has only zero below it (assuming that the poset has a least element, its "zero").
11. An element of a set that is not itself a set; an urelement.
12. An age group division in hockey for nine- to eleven-year-olds.

## Etymology
From Middle English attome, from Middle French athome, from Latin atomus (“smallest particle”), from Ancient Greek ἄτομος (átomos, “indivisible”), from ἀ- (a-, “not”) + τέμνω (témnō, “to cut”, o-grade in τομ-) + -ος (-os). Atoms are so named because they were historically thought up as to be the smallest unit of matter, and thus indivisible. Doublet of atomus.

## Easily confused with
- **ATP** (https://plainspell.com/en/vs/atom-vs-atp)
- **att** (https://plainspell.com/en/vs/atom-vs-att)
- **ATV** (https://plainspell.com/en/vs/atom-vs-atv)
- **ATR** (https://plainspell.com/en/vs/atom-vs-atr)
- **auto** (https://plainspell.com/en/vs/atom-vs-auto)
- **atop** (https://plainspell.com/en/vs/atom-vs-atop)
- **Avon** (https://plainspell.com/en/vs/atom-vs-avon)
- **atta** (https://plainspell.com/en/vs/atom-vs-atta)
- **AWOL** (https://plainspell.com/en/vs/atom-vs-awol)
- **axon** (https://plainspell.com/en/vs/atom-vs-axon)
- **atoms** (https://plainspell.com/en/vs/atom-vs-atoms)
- **axiom** (https://plainspell.com/en/vs/atom-vs-axiom)
- **atone** (https://plainspell.com/en/vs/atom-vs-atone)
- **atomic** (https://plainspell.com/en/vs/atom-vs-atomic)
- **at** (https://plainspell.com/en/vs/at-vs-atom)
- **AM** (https://plainspell.com/en/vs/am-vs-atom)
- **ao** (https://plainspell.com/en/vs/ao-vs-atom)
- **ago** (https://plainspell.com/en/vs/ago-vs-atom)
- **arm** (https://plainspell.com/en/vs/arm-vs-atom)
- **aim** (https://plainspell.com/en/vs/aim-vs-atom)

## Common misspellings (5)
`aotm`, `atmo`, `atomm`, `attom`, `taom`

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/atom