cog
/kɒɡ/
"cog" is a 3-letter English headword indexed on PlainSpell.
The verdict
“cog” is a moderately-common English word, ranked #28,496 in English word frequency and used as a noun.
- #28,496
- frequency rank, English
- 3
- letters
- 20
- confusable pairs
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A tooth on a gear.
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 | cog |
| Language | English |
| Part of speech | Noun |
| IPA | /kɒɡ/ |
| Letters | 3 |
| Frequency rank | #28,496 |
| Misspellings tracked | 0 |
| Confusable pairs | 20 |
| Source | Wiktionary (kaikki.org) |
Where “cog” sits in English frequency
Spelling & Dictionary Insight
The English entry for cog is 3 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /kɒɡ/. Corpus data places it at rank #28,496 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 5 distinct senses for this headword, so context determines which meaning a reader should apply.
No misspelling variants are generated for cog in our index, a sign its spelling follows regular English conventions. It also participates in 20 confusable-pair relationships, "CT", "CR", "cs", and more, a pairing that trips writers up because the two words share enough sound or shape to blur together.
Etymologically, the entry records: Inherited from Middle English cogge, from Old Norse *kogge, *koggr (see Old Swedish kogge, kogger), from Proto-Germanic *kuggō (“cog, swelling”), from Proto-Indo-European *gugā (“hump, ball”), from *gēw- (“to bend, arch”). Compare Lithuanian gugà (“pommel, … The correct English form is cog, spelled C-O-G.
Definition
- 1A tooth on a gear.
- 2A gear; especially, a cogwheel.
- 3An unimportant individual in a greater system.
- 4A projection or tenon at the end of a beam designed to fit into a matching opening of another piece of wood to form a joint.
- 5One of the rough pillars of stone or coal left to support the roof of a mine.
Etymology
Inherited from Middle English cogge, from Old Norse *kogge, *koggr (see Old Swedish kogge, kogger), from Proto-Germanic *kuggō (“cog, swelling”), from Proto-Indo-European *gugā (“hump, ball”), from *gēw- (“to bend, arch”). Compare Lithuanian gugà (“pommel, hump, hill”). Cognates includes: Swedish kugg, kugge (“cog tooth”), Norwegian kugg (“cog”). The meaning of “cog” in carpentry derives from association with a tooth on a cogwheel. Compare Old Swedish koggavidher (“cog wood”), “wood reserved for a millwheel”. See also dialectal English cag (“stump”), keg; Old Norse kaggi (“keg”) + -gi (diminutive suffix), from the Germanic base *kagô (“bush, branch, stalk, stump”); also found in Bavarian Kag (“the stalk or stem of a cabbage”); dialectal Swedish kage (“treestump; piece of wood; post”), kagg or kagge (“scythe handle”); Norwegian Nynorsk kage or kagge (“low lying bush, small tree”), dialectal kagg (“scythe handle”); Old English ċeacga (“broom, furze, gorse”), whence English chag (“branch”), also Old English cyċġel, English cudgel (“knotty club”). The ultimate origin could be related to English cog (“cargo boat”) (Dutch kogge), probably named for its “round swollen” appearance.
This word in other languages
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 “cog”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is C-O-G - every other letter order is a misspelling in standard orthography.
- Say it as /kɒɡ/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Don't mix it up with “CT” - see the side-by-side comparison. cog vs CT
- 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.