firth
/fɜːθ/
"firth" is a 5-letter English headword indexed on PlainSpell.
The verdict
“firth” is a moderately-common English word, ranked #22,972 in English word frequency and used as a noun.
- #22,972
- frequency rank, English
- 5
- letters
- 7
- tracked misspellings
- 20
- confusable pairs
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - An arm or inlet of the sea; a river estuary.
Visual similarity to commonly confused words
How many letter changes separate each confused pair (Levenshtein distance, normalized).
Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).
| Property | Value |
|---|---|
| Headword | firth |
| Language | English |
| Part of speech | Noun |
| IPA | /fɜːθ/ |
| Letters | 5 |
| Frequency rank | #22,972 |
| Misspellings tracked | 7 |
| Confusable pairs | 20 |
| Source | Wiktionary (kaikki.org) |
Where “firth” sits in English frequency
Spelling & Dictionary Insight
The English entry for firth is 5 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /fɜːθ/. Corpus data places it at rank #22,972 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. The dominant gloss from Wiktionary reads: "An arm or inlet of the sea; a river estuary.".
Our generated misspelling index lists 7 likely wrong-spelling variants for firth, with forms such as "ffirth", "firht", and "firrth". Each of these forms differs from the correct spelling by one small edit: a doubled letter, a dropped silent letter, or a substituted vowel. It also participates in 20 confusable-pair relationships, "fit", "fish", "fort", and more, a pairing that trips writers up because the two words share enough sound or shape to blur together.
Etymologically, the entry records: Borrowed from Scots firth, furth, from Northern Middle English fyrth, from either or both of Old English ford and Old Norse fjǫrðr (“firth, fjord”), from Proto-Germanic *ferþu, *ferþuz (“inlet, fjord”), from Proto-Indo-European *pértus (“crossing”), from *p… The correct English form is firth, spelled F-I-R-T-H.
Definition
- 1An arm or inlet of the sea; a river estuary.
Etymology
Borrowed from Scots firth, furth, from Northern Middle English fyrth, from either or both of Old English ford and Old Norse fjǫrðr (“firth, fjord”), from Proto-Germanic *ferþu, *ferþuz (“inlet, fjord”), from Proto-Indo-European *pértus (“crossing”), from *per- (“to carry forth”) + *-tus (suffix forming action nouns from verb roots). The English word is a doublet of fjord, ford, port, and fjard.
This word in other languages
Common misspellings
Also misspelled as: ffirth,firht,firrth,firthh,firtth,fitrh,ifrth
Misspelling Pattern Breakdown
How far each generated variant is from the correct spelling of firth - counted as single-character edits (an insertion, a deletion, or a substituted letter). The larger the bar, the easier the typo is to spot; one-edit slips are the ones that sneak past readers.
Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.
Frequently Asked Questions
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Using “firth”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is F-I-R-T-H - every other letter order is a misspelling in standard orthography.
- Say it as /fɜːθ/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Don't mix it up with “fit” - see the side-by-side comparison. firth vs fit
- Browse more English words and confusable pairs in the same reference. English words
Data Source
Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.