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Definition of diameter noun from the Oxford Advanced Learner's Dictionary

diameter

noun
 
/daɪˈæmɪtə(r)/
 
/daɪˈæmɪtər/
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  1. a straight line going from one side of a circle or any other round object to the other side, passing through the centre
    • The diameter of the tree trunk was more than a metre.
    • in diameter The dome is 42.3 metres in diameter.
    compare radius
    Extra Examples
    • The mirror is 25cm in diameter.
    • The tubes have an internal diameter of 2 mm.
    • a method of calculating the diameter of the earth
    • The radius of a circle is half its diameter.
    Topics Colours and Shapesc1, Maths and measurementc1
    Oxford Collocations Dictionaryadjective
    • inner
    • inside
    • internal
    verb + diameter
    • calculate
    • determine
    • estimate
    preposition
    • in diameter
    See full entry
  2. (specialist) a measurement of the power of an instrument to magnify something
    • a lens magnifying 300 diameters (= making something look 300 times larger than it really is)
  3. Word Originlate Middle English: from Old French diametre, via Latin from Greek diametros (grammē) ‘(line) measuring across’, from dia ‘across’ + metron ‘measure’.
See diameter in the Oxford Advanced American DictionarySee diameter in the Oxford Learner's Dictionary of Academic English
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noun
 
 
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