rectangular

Etymology

The OED takes it as from Medieval Latin rectangulum (“rectangle”) with the English suffix -ar, on the model of rectangle;^[2] Merriam-Webster likewise derives it from rectangulus (“having a right angle”).^[3] Etymonline and the Shorter Oxford see the influence of Middle French rectangulaire, recorded in 1571,^[4][5][2] and Johnson gave the French word as its source.^[6] The OED also compares rectangularis, recorded by 1634.^[2] The Latin word is an alteration of rectiangulus (“right-angled”), recorded from the 6th century,^[2] from Latin rēctus (“straight, right”) and angulus (“angle”),^[2][7] and Etymonline traces rēctus to Proto-Indo-European *reg- (“to move in a straight line”).^[4]

Earliest recorded meaning

Shaped like a rectangle, with four sides and four right angles, and of a solid body, having rectangular sides or section: before about 1560, in Leonard Digges's Pantometria, printed in 1571.^[2] Merriam-Webster dates its first use to about 1560,^[3] but Etymonline, Dictionary.com and the Shorter Oxford date the word only to the early 17th century.^[4][8][5]

Semantic evolution

In mathematics it was used from 1624 of a right-angled triangle, a sense now covered by right-angled.^[2] From 1646 it also meant placed or lying at right angles,^[2][5] and since 1703 it has meant having parts or lines at right angles to one another.^[2] Johnson (1755) defined it as "right angled; having angles of ninety degrees".^[6] A figurative use for "formal, stiff" is recorded only from 1826 to 1842.^[2] Etymonline notes that it outlived rivals such as rectangulous, recorded in the 1610s.^[4]

Timeline

• c. 1560 – shaped like a rectangle; of a solid, with rectangular faces or section.^[2][3]
• 1624 – of a triangle, right-angled.^[2]
• 1646 – placed at right angles.^[2][5]
• 1703 – with parts or lines at right angles to each other.^[2]
• 1826 – figurative, formal, stiff (to 1842).^[2]
• 1837 – in crystallography, orthorhombic (now rare).^[2]

Meanings

Adjective

1. Shaped like a rectangle: a rectangular lawn.^[9][3][2]
2. Of a solid, having faces, edges or a cross-section that meet at right angles or are rectangles: rectangular blocks of stone.^[3][2][9]
3. Crossing, lying or meeting at right angles; perpendicular: rectangular coordinates.^[9][3][2]

Word family

• rectangularity
• rectangularly
• unrectangular
• nonrectangular
• subrectangular
• rectangular coordinates

Related words

• rectangle
• angular
• angle
• right

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n o p q r s Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ a b c d Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ a b c d Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
6. ^ 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.
7. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
8. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
9. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins