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# cog

«cog» in Mova's school dictionary: **one of the teeth around the edge of a wheel in a machine…** — its meaning for a pupil, its sense in the lessons and examples, with 2 sentences of Mova's corpora that use it.

### part of speech

noun (a cog, cogs)

### meaning for a pupil

1) A cog is one of the teeth around the edge of a wheel in a machine; a whole wheel with teeth is also called a cog or cogwheel (gear). [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/C/cog/#m1)

2) (figurative) «A cog in the machine» is a person who has a small part in a big organisation and feels unimportant. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/C/cog/#m2)

3) (UK, slang) In some places, «to cog» means to copy someone's homework. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/C/cog/#m3)

### sense in the lessons

In science and DT lessons, cogs (gears) show how turning one wheel can turn another faster, slower or the other way; a small cog turning a big cog makes it turn more slowly but with more force. In stories, «the cogs were turning» means someone was thinking hard. Phrases: «a cog in the machine», «cogs turning», «cogwheel».

### examples

- The clock's cogs turned slowly behind the glass. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/C/cog/#x1)
- When the big cog turns once, the small cog turns three times. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/C/cog/#x2)
- A missing tooth on the cog jammed the machine. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/C/cog/#x3)
- You could see the cogs turning in his head as he worked out the puzzle. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/C/cog/#x4)
- He felt like a tiny cog in a huge company. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/C/cog/#x5)
- We built a cog model from cardboard and pins. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/C/cog/#x6)
- The bike's chain runs over cogs at the back wheel. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/C/cog/#x7)

### note

Countable noun: one cog, two cogs. In maths problems with gears, if a big cog has 30 teeth and a small one 10, the small cog turns 3 times for each turn of the big one (30 ÷ 10 = 3).

### In the corpora

- [Picture a puzzle card at a science club: «A chain wheel has 40 teeth and the back cog 20.](https://md.mova.elamur.ai/free/en/corpora/school/technology/42-olympiad-machines-at-home-and-in-the-factory/2/)
- [A bigger back cog makes pedalling easier but slower, good for hills; a smaller back cog makes it harder but faster.](https://md.mova.elamur.ai/free/en/corpora/school/technology/42-olympiad-machines-at-home-and-in-the-factory/7/)

### Trees and pragmatics

[Every meaning and example of «cog» parsed by Mova](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/C/cog/), each sentence with its dependency tree and frames.