longitude

Etymology

It is inherited from Middle English longitude,^[2] partly borrowed from Middle French longitude, recorded in Old French from 1314 for length, in astronomy from before 1324,^[3] and partly directly borrowed from Latin longitūdō (“length, extent, duration”),^[3][4][5][6] from longus (“long”), with the suffix -tūdō (-tude).^[3][6][7] In British sources post-classical Latin used longitūdō for geographical longitude from the 12th century and for celestial longitude in the 14th.^[3] The Anglo-Norman word is recorded from the third quarter of the 13th century in the sense "length".^[8] The American Heritage Dictionary refers the Latin adjective to Proto-Indo-European *del-.^[9]

Earliest recorded meaning

The angular distance of a place east or west of a standard meridian, and in astronomy of a heavenly body: 1391, in Chaucer's Treatise on the Astrolabe.^[3][4] The Middle English Dictionary also records the senses "length, height".^[2]

Semantic evolution

The geographical sense comes from the ancient maps of the known world, which were longer from west to east than from north to south: the east–west dimension was the "length" of the earth, the north–south one its "breadth", or latitude.^[10][5] In astronomy the word followed the use of latitude for distance from the ecliptic.^[3] The plain sense of length or tallness, recorded from the early 15th century,^[3][2] is now chiefly humorous in British use,^[11] and the sense of duration, from 1596, became rare after the 17th century.^[3][11] Johnson (1755) gave "length; the greatest dimension" first and "the circumference of the earth measured from any meridian" second.^[12] From 1665 to 1791 the longitude could also mean a method of finding longitude at sea, or a clock made for it.^[3]

Timeline

• 1391 – angular distance east or west of a meridian, in geography and astronomy.^[3][4]
• before 1425 – length; formerly also height.^[3]
• before 1475 – extent from east to west (now obsolete).^[3]
• 1595 – the distance between two places measured as the angle between their meridians.^[3]
• 1596 – duration, long continuance.^[3]
• 1665 – a method of finding longitude at sea (obsolete by 1791).^[3]

Meanings

Noun

1. The angular distance of a place east or west of the prime meridian at Greenwich, measured in degrees: The island lies at a longitude of about 30 degrees west.^[13][14][3]
2. (astronomy) Celestial longitude: the angular distance of a heavenly body eastward from the vernal equinox, measured along the ecliptic.^[13][3]
3. Length; the measure along the longest line (now chiefly humorous in British use).^[14][11][3]
4. (archaic) Long duration.^[14][11][3]

Word family

• longitudinal
• celestial longitude

Related words

• latitude
• long

Usage notes

The OED's first edition (1903) gave only the pronunciation with /-ndʒ-/; the pronunciation with /-ŋɡ-/ is recorded in British dictionaries from the mid 20th century.^[3]

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
3. ^ a b c d e f g h i j k l m n o p q r s t Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
4. ^ a b c Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
5. ^ a b Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
7. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
8. ^ Anglo-Norman Dictionary (AND2), Aberystwyth University, anglo-norman.net (2nd ed., 2005–)
9. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
10. ^ Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
11. ^ 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
12. ^ 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 Collins English Dictionary (2023), Glasgow: HarperCollins
14. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster