isometric

Etymology

It is formed from English iso- + -metric, literally "of the same measure",^[2] or, in other dictionaries, from Ancient Greek ἰσομετρία (isometría, “equality of measure”) with the suffix -ic,^[3][4][5][6] or from the related Greek adjective meaning "of equal measure".^[7][8][9] The Greek words are formed from ἴσος (ísos, “equal”) and μέτρον (métron, “a measure”),^[2][7][9] which is related to measure and meter.^[10][9] The OED compares French isométrique, used in mathematics from 1832.^[3] The physiological sense was borrowed from German isometrisch, used in that sense by the physiologist Adolf Fick in 1882.^[3][7][2]

Earliest recorded meaning

Of a method of projection in drawing in which the three main axes are equally inclined to the plane: 1840, in the Penny Cyclopaedia.^[3][7] Etymonline dates the word to 1838,^[2] and Merriam-Webster Unabridged to about 1855, the date the OED gives for the general sense "of equal measure".^[10][3]

Semantic evolution

From the drawing method the word passed to crystallography, for the system of crystals with three equal axes at right angles (1868), and to physics, for changes that take place at constant volume (1873).^[3][2] In physiology it was used from 1891 of muscle contraction against a resistance, without the muscle shortening.^[3][7] This sense came from German, and Etymonline dates it to 1889.^[3][2] This sense gave the noun isometrics, exercises in which muscles are pressed against each other or against an unyielding object, an American word of 1962 that Barnhart calls a recent vogue term.^[7][3] Mathematics added "related by an isometry" in 1952.^[3]

Timeline

• 1840 – of a method of drawing or projection with the three main axes equally inclined.^[3][7]
• 1855 – of equal measure or dimensions.^[3]
• 1868 – in crystallography, having three equal axes at right angles.^[3]
• 1873 – in physics, taking place at constant volume.^[3]
• 1891 – of muscle contraction against resistance without shortening.^[3][7]
• 1962 – isometrics, a system of static exercises.^[3][7]

Meanings

Adjective

1. Having equal measurements or dimensions.^[11][10][3]
2. Of or drawn in a kind of projection in which the three main axes are equally inclined and all lines along them are drawn to the same scale: an isometric drawing of the engine block.^[3][10]
3. (physiology) Of muscle contraction that works against resistance without the muscle shortening.^[11][10][3]
4. (crystallography) Having three equal axes at right angles; cubic.^[11][3]
5. (physics) Taking place at constant volume.^[10][3]

Word family

• isometrically
• anisometric
• isometrics

Related words

• isometry
• isotonic
• meter
• 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 g h i j k l m n o p q r s t u Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
4. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
6. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
7. ^ a b c d e f g h i Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
8. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
9. ^ a b c Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
10. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
11. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins