perimeter

Etymology

It is inherited from Middle English perimetre,^[2][3][4] borrowed from Latin perimetros (“circumference”),^[5][2][3][4] from Ancient Greek περίμετρος (perímetros), a noun use of the Greek adjective meaning "going round, circumferential".^[5][3] The Greek word is formed from περι- (peri-, “around”) and μέτρον (métron, “measure”),^[5][2][6][7] and Etymonline traces the second part to Proto-Indo-European *me- (“to measure”).^[2] The OED compares the Greek neuter περίμετρον (perímetron),^[5] which Dictionary.com gives as the direct Greek source.^[8] Collins, Hoad, Klein and Dictionary.com instead take the modern word through French périmètre and date it to the 16th century,^{[9][10][7][8]} while the OED, Barnhart and the Oxford Dictionary of English find it in late Middle English.^[5][3][11]

Earliest recorded meaning

A continuous line forming the boundary of a figure or a surface; a circumference: before 1425, in an English translation of Guy de Chauliac's Grande Chirurgie.^[5] Barnhart dates the first record to probably before 1425,^[3] and Etymonline to the early 15th century.^[2]

Semantic evolution

The word began as a term of geometry, for the line round a figure and for the length of that line.^[5][6] Johnson (1755) defined it as the sum of all the sides that bound any figure, whether straight or curved.^[12] From the early 17th century it was used more loosely and figuratively for a ring or space around something, an edge or a limit, as in Ben Jonson's Magnetick Lady (before 1637); in this use it is sometimes confused with parameter.^[5] The military sense, the defended boundary of a position, is recorded from 1861 in the OED,^[5] and by 1943 in Etymonline;^[2] it spread to the boundary of a prison, an airfield or an airport.^[5] In ophthalmology a perimeter has been an instrument for measuring the field of vision since 1875,^[5][9] and in basketball the word has meant the area beyond the three-point line since 1959,^[5] when it also came into use as an adjective for players and shots from that area.^[13]

Timeline

• before 1425 – the boundary line of a figure or surface; a circumference.^[5][3]
• 1585–95 – the date Dictionary.com gives for the word, borrowed through French.^[8]
• before 1637 – figurative: a ring around something, an edge or limit.^[5]
• 1755 – Johnson defines it as the sum of the sides bounding a figure.^[12]
• 1861 – military: the defended boundary of a position.^[5]
• 1875 – ophthalmology: an instrument for measuring the field of vision.^[5]
• 1959 – basketball: the area beyond the three-point line; also as an adjective.^[5][13]

Meanings

Noun

1. The boundary of a closed plane figure: the perimeter of a triangle.^[13][9][5]
2. The length of such a boundary, as the sum of the sides of a polygon.^[13][9][5]
3. The outer edge or boundary of any area: Guards walked the perimeter of the airfield every hour.^[9][13][5]
4. The fortified boundary of a military position.^[5][6]
5. In basketball, the area of the court away from the basket, beyond the three-point line.^[13][5]
6. An instrument for measuring the extent of the field of vision.^[9][5]

Adjective

1. In basketball, playing or scoring mostly from the perimeter: a perimeter shooter.^[13]

Word family

• perimetric
• perimetrically
• perimeterless
• perimetral
• perimetry
• isoperimeter

Related words

• meter
• diameter
• parameter
• periphery
• measure

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ a b c d e f Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
4. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
5. ^ a b c d e f g h i j k l m n o p q r s t u v w Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
6. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
7. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
8. ^ a b c Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
9. ^ a b c d e f Collins English Dictionary (2023), Glasgow: HarperCollins
10. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
11. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
12. ^ a b Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
13. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster