# signal

> English word · Noun · IPA /ˈsɪɡnəl/ · frequency rank #2,406

## Definitions
1. A sequence of states representing an encoded message in a communication channel.
2. Any variation of a quantity or change in an entity over time that conveys information upon detection.
3. A sign made to give notice of some occurrence, command, or danger, or to indicate the start of a concerted action.
4. An on-off light, semaphore, or other device used to give an indication to another person.
5. An on-off light, semaphore, or other device used to give an indication to another person.
6. An electromagnetic action, normally a voltage that is a function of time, that conveys the information of the radio or TV program or of communication with another party.
7. An action, change or process done to convey information and thus reduce uncertainty.
8. A token; an indication; a foreshadowing; a sign.
9. Useful information, as opposed to noise.
10. A simple interprocess communication used to notify a process or thread of an occurrence.
11. A signalling interaction between cells

## Etymology
From Old French segnal, seignal or Medieval Latin signāle; noun use of the neuter of Late Latin signālis, from Latin signum; verb use from 1805, as a shortened from signalize (1650s).

## Easily confused with
- **Sina** (https://plainspell.com/en/vs/signal-vs-sina)
- **signs** (https://plainspell.com/en/vs/signal-vs-signs)
- **Sinai** (https://plainspell.com/en/vs/signal-vs-sinai)
- **signed** (https://plainspell.com/en/vs/signal-vs-signed)
- **spinal** (https://plainspell.com/en/vs/signal-vs-spinal)
- **signup** (https://plainspell.com/en/vs/signal-vs-signup)
- **signor** (https://plainspell.com/en/vs/signal-vs-signor)
- **signer** (https://plainspell.com/en/vs/signal-vs-signer)
- **signet** (https://plainspell.com/en/vs/signal-vs-signet)
- **signals** (https://plainspell.com/en/vs/signal-vs-signals)
- **sign** (https://plainspell.com/en/vs/sign-vs-signal)
- **sigma** (https://plainspell.com/en/vs/sigma-vs-signal)
- **Siena** (https://plainspell.com/en/vs/siena-vs-signal)
- **Segal** (https://plainspell.com/en/vs/segal-vs-signal)
- **signage** (https://plainspell.com/en/vs/signage-vs-signal)

## Common misspellings (9)
`isgnal`, `sginal`, `siganl`, `siggnal`, `signall`, `signla`, `signnal`, `singal`, `ssignal`

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