millimeter (noun) — An SI/MKS unit of measure, the length of 1/1000 of a meter. Symbol: mm
millimetre sounds exactly like millimeter but has a different meaning and spelling. Mixing these up is one of the most common spelling mistakes in English.
millimeter
noun
An SI/MKS unit of measure, the length of 1/1000 of a meter. Symbol: mm
millimetre
noun
An SI/MKS unit of measure, the length of 1/1000 of a metre. Symbol: mm
Full definition →How to Remember the Difference
- → Focus on meaning first — once you know what each word means, the correct spelling follows naturally.
- → Write a test sentence for each word and save it as a reference.
- → When in doubt, look up the definition — if it doesn't match your sentence, switch to the homophone.
Frequently Asked Questions
What is a homophone of millimeter?
millimetre is a homophone of "millimeter". They sound identical when spoken but have different meanings and spellings.
What is the difference between millimeter and millimetre?
"millimeter" means: An SI/MKS unit of measure, the length of 1/1000 of a meter. Symbol: mm. "millimetre" means: An SI/MKS unit of measure, the length of 1/1000 of a metre. Symbol: mm. They sound the same but are used in completely different contexts.
What is a homophone?
A homophone is a word that sounds exactly like another word but has a different meaning and often a different spelling. Examples include "their / there / they're", "to / too / two", and "millimeter / millimetre". Homophones are a common source of spelling and grammar mistakes.
How do I remember the difference between millimeter and millimetre?
A good strategy is to memorize a short sentence that uses each word correctly, then recall that sentence when you are unsure. For example, focus on the meaning first — then let the spelling follow from context. Reading and writing regularly also helps these distinctions become automatic.