Longman Dictionary of Contemporary English homepage

Date: 1300-1400
Language: Old French
Origin: diametre, from Greek diametros 'measure across', from metron 'measure'

diameter

 noun
     
Related topics: Maths
di‧am‧e‧ter [countable]
HMHM a straight line from one side of a circle to the other side, passing through the centre of the circle, or the length of this line
3 inches/1 metre etc in diameter
Draw a circle six centimetres in diameter.
diameter of
The diameter of the Earth is about 13,000 km.
Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary.

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