redefinevsredlineWhich spelling fits?

Quick tell: redefine is a verb, redline is a noun, so they fill different roles in a sentence.

Which to use

“redefine” is a verb and “redline” is a noun - they look or sound alike but fill different roles in a sentence.

#25,897
“redefine” frequency rank
#43,873
“redline” frequency rank
69770
confusion score

Side-by-Side Comparison

Feature redefine redline
Definition To define again or differently. A drawing, document, etc. that has been marked for correction or modification.

Letter map: redefine vs redline

Shared letters muted; letters that set redefine and redline apart highlighted. Shared run: 6. redefine runs 8 letters (CVCVCVCV) against redline's 7 (CVCCVCV) - the length gap alone is often enough to separate them once you know to check it.

8 ch
redefine
7 ch
redline

Grammar separator: redefine vs redline

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: redefine is averb and redlineanoun. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 69770, derived from the frequency rank of both members and their visual similarity.

redefine is recorded at frequency rank #25,897, classified as averb. redline is at rank #43,873, tagged as anoun, pronounced /ˈɹɛd.laɪn/.

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 69770, this pair ranks #53,199 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of redefine vs redline

Shared letters: deinr. Private to "redefine": f. Private to "redline": l.

"redefine" · 8 letters · shape CVCVCVCV  ·  "redline" · 7 letters · shape CVCCVCV

Known mistypes of this pair

  • redefine ← erdefine · rdeefine · reddefine · redeffine · redefien · redefinne · redefnie · redeifne
  • redline ← erdline · rdeline · reddline · redilne · redlien · redlinne · redlline · redlnie

Frequently Asked Questions

Is swapping "redefine" for "redline" ever safe?
No - they are not even the same part of speech. "redefine" is a verb and "redline" a noun, so a sentence built for one is usually ungrammatical with the other.
In ordinary English text, does "redefine" or "redline" show up more?
"redefine" is the more common of the two: it sits at frequency rank #25,897 in our English list, against #43,873 for "redline". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Pair "redefine" vs "redline" is on the table, pick a follow-up below.

  • Full dictionary entry for "redefine" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "redline" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #53,199 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "redefine" and "redline" also get mixed up with nearby pairs, the highest-scored neighbour is "recliner vs redline". 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 #53,199 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