cog

/kɒɡ/

//kɒɡ// noun

By · According to Wiktionary data (CC BY-SA) ·

"cog" is a 3-letter English headword indexed on PlainSpell.

The verdict

“cog” sits in 20 confusable pairs (corpus #28,496) as a noun. The look-alike neighbours are the real trap.

#28,496
frequency rank, English
5,599
“C” headwords
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A tooth on a gear.

Corpus desk

Index EN-cog · cog · English

cog · rank #28,496 · 0 variants · 20 confusables

  • FREQ-MID #28,496
  • LEN-MID 3 letters
  • VOW-1 1 vowel
  • CONFUS-HIGH 20 pairs
  • VAR-0 0 variants
  • BOOK-DENSE 5,599
  • PHOTO-FINISH Cleo

Nearest frequency peer: Cleo (-1 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Frequency neighbours of confusable “cog”

Peers at similar corpus weight, separate from look-alike pairs below

corpus weight

What this shows Bars place “cog” against nearest ranked English headwords, not a reprint of the confusable-pair desk.

Source FrequencyWords open word-frequency list As of September 3, 2026

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

cog vs CT
0% similar
cog vs CR
0% similar
cog vs cs
33% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for cog
PropertyValue
Headwordcog
LanguageEnglish
Part of speechNoun
IPA/kɒɡ/
Letters3
Frequency rank#28,496
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Corpus rank beside confusables of “cog”

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right).coglands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

The axis is logarithmic, with each marked tick roughly ten times rarer than the last. Same rarity band neighbours include “Cleo” (#28,495), “coloration” (#28,498), “connective” (#28,499). Among 5,599 “C” headwords, “cog” is #28,496. Source: FrequencyWords open word-frequency list.

Easy to mix with look-alikes

The spelling risk for cog is neighbouring look-alikes ("CT", "CR", …), not just typos; it is anoun pronounced /kɒɡ/. Frequency #28,496 among 5,599 “C” headwords. 5 recorded senses keep meaning in play.

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

  1. 1
    A tooth on a gear.
  2. 2
    A gear; especially, a cogwheel.
  3. 3
    An unimportant individual in a greater system.
  4. 4
    A 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.
  5. 5
    One of the rough pillars of stone or coal left to support the roof of a mine.

Recorded use

Wiktionary examples

These source excerpts show how cog appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. She said: " We're not wasting time. While the cogs of Parliament continue to whir, we will continue to work on the rolling stock and infrastructure strategy, the national transport integrated strategy, and our accessibility roadmap.
  2. just a cog in the machine

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

leva(Español)dent(Français)Zahn(Deutsch)dente(Português)

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

How do you spell "cog"?
"cog" is spelled C-O-G. The IPA pronunciation is /kɒɡ/.
What does "cog" mean?
As a noun, "cog" means: A tooth on a gear.
What words are commonly confused with "cog"?
"cog" is commonly confused with "CT", "CR", "cs". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "cog"?
The IPA (International Phonetic Alphabet) transcription for "cog" is /kɒɡ/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "cog"?
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 ... See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "cog", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 3 letters (nearest by frequency rank).

CDR#28,484CCS#28,483bla#28,468EEG#28,526

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

Source: FrequencyWords open word-frequency list