sigmavssignalTell them apart

Which to use

“sigma” and “signal” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#14,835
“sigma” frequency rank
#2,406
“signal” frequency rank
17241
confusion score

Side-by-Side Comparison

Feature sigma signal
Definition The eighteenth letter of the Classical and Modern Greek alphabets (Σ, σ), the twentieth letter of Old and Ancient. A sequence of states representing an encoded message in a communication channel.

Where the eye mixes sigma and signal

Muted = shared; highlighted = the visual trap. They share 4 letters in sequence.

5 ch
sigma
6 ch
signal

Look-alike desk: sigma vs signal

A purely visual mix-up. sigma (/ˈsɪɡmə/) and signal (/ˈsɪɡnəl/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by 1 letter(s) in length. Our composite confusion score for this pair is 17241, derived from the frequency rank of both members and their visual similarity.

sigma is recorded at frequency rank #14,835, classified as anoun, pronounced /ˈsɪɡmə/. signal is at rank #2,406, tagged as anoun, pronounced /ˈsɪɡnəl/.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 17241, this pair ranks #452,708 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of sigma vs signal

Shared letters: agis. Private to "sigma": m. Private to "signal": ln.

"sigma" · 5 letters · shape CVCCV  ·  "signal" · 6 letters · shape CVCCVC

Known mistypes of this pair

  • sigmaisgma · sgima · sigam · siggma · sigmma · simga · ssigma
  • signalisgnal · sginal · siganl · siggnal · signall · signla · signnal · singal

Frequently Asked Questions

Can "sigma" and "signal" be used interchangeably?
No. They are said differently (/ˈsɪɡmə/ versus /ˈsɪɡnəl/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Frequency check: "sigma" vs "signal" - which ranks higher?
"signal" is the more common of the two: it sits at frequency rank #2,406 in our English list, against #14,835 for "sigma". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Eye-level mix-up between "sigma" and "signal" is sorted above. Next: full entries or other pairs that share a letter shape.

  • Full dictionary entry for "sigma" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "signal" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #452,708 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "sigma" and "signal" also get mixed up with nearby pairs, the highest-scored neighbour is "sigma vs Sitka". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #452,708 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list