Definition of perimeter in English:

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Pronunciation: /pəˈrimidər/


1The continuous line forming the boundary of a closed geometric figure: the perimeter of a rectangle
More example sentences
  • He compares the areas of figures with equal perimeters and volumes of solids with equal surface areas, proving a result due to Zenodorus that the sphere has greater volume than any regular solid with equal surface area.
  • The number four, for example, would be the ratio of the perimeter of a square to one of its sides and also the ratio of the area of a square to the area of a square whose side is half the original.
  • Then these rings also have the additional property that both the inner perimeters are equal and the outer perimeters are equal.
circumference, outside, outer edge
1.1The outermost parts or boundary of an area or object: the perimeter of the garden figurative my presence on the perimeter of his life
More example sentences
  • He said it was the landlord of the estate who had replaced the perimeter fence around the whole of the industrial area.
  • One is a low-voltage electric fence around the perimeter of your garden.
  • The only sure way of deterring them is to have an electric fence built around the perimeter of the garden.
boundary, border, limits, bounds, confines, edge, margin, fringe(s), periphery, borderline, verge
literary bourn, marge
1.2A defended boundary of a military position or base.
Example sentences
  • Bitter fighting ensued and the enemy overran forward elements, infiltrated the perimeter and rendered friendly positions untenable.
  • Ahead of us is a large cave entrance protected by a perimeter of military guards and equipment.
  • The troops were tasked with planning the defense of the squadron and performing defensive operations around the base perimeter.
1.3 Basketball An area away from the basket, beyond the reach of the defensive team: he was very patient in working the ball around the perimeter
More example sentences
  • That is to say, whenever the ball is on the perimeter, 3 defensive players are between the player with the ball and basket.
  • With reduced defensive contact on the perimeter, point guards can do their jobs with less harassment.
  • More than anything, the team needs his defense on the perimeter against more athletic swingmen.
2An instrument for measuring the extent and characteristics of a person’s field of vision.



Pronunciation: /ˌperəˈmetrik/
Example sentences
  • Definitive perimetric (visual field) evidence, detailed ophthalmoscopic evidence, or both confirm the diagnosis of open-angle glaucoma.
  • In the short term the low cost, widespread acceptance, and availability of static visual acuity and perimetric measures justifies their use.


Late Middle English: via Latin from Greek perimetros, based on peri- 'around' + metron 'measure'.

  • Perimeter is simply a fancy way of saying ‘the distance round’ for it comes via Latin from Greek perimetros, based on peri- ‘around’ and metron ‘measure’.

Words that rhyme with perimeter

limiter, scimitar, velocimeter

For editors and proofreaders

Syllabification: pe·rim·e·ter

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