hemisphere

Etymology

It is inherited from Middle English hemisperie, also emisperie,^[2][3][4] borrowed from Late Latin hēmisphaerium,^[2][5][3] from Ancient Greek ἡμισφαίριον (hēmisphaírion),^[2][5][3] from ἡμι- (hēmi-, “half”) and σφαῖρα (sphaîra, “ball, sphere”).^[2][5][6] Merriam-Webster takes the second part as a diminutive, "small sphere".^[7] The present form came in the 15th and 16th centuries through Old French emispere, also emisphere,^[2][8][3] now hémisphère.^[2][8] It is formed like the English hemi- and sphere,^[5][1] and displaced the native Old English healftrendel (“half-sphere”).^[1]

Earliest recorded meaning

Half of the celestial sphere, especially the half of the sky seen above the horizon: about 1374, in Chaucer's Troilus and Criseyde,^[2][4] about 1385 in Barnhart.^[3] Chaucer used the word three times, as hemysperie and emysperies.^[4]

Semantic evolution

The word began in astronomy, for half of the heavens, and Merriam-Webster still records the older sense "the sky overhead" as obsolete.^[2][7][5] Spellings with -spere and -sphere replaced hemisperie from the 15th century, and Barnhart dates the modern spelling to 1532.^[8][3] The figurative sense, a realm or sphere of action or thought, appears about 1504.^[2] From 1555 it was used of either half of the earth, divided by the equator into the Northern and Southern Hemispheres, or into the Eastern and Western Hemispheres;^[2][5][9] the plain geometrical sense, half of any sphere, is recorded only from 1585.^[2] A map of half the globe was called a hemisphere from 1706,^[2] and in anatomy each half of the cerebrum since 1804.^[2][5] Johnson (1755) defined it as half of a globe cut through its centre.^[10]

Timeline

• c. 1374 – half of the celestial sphere, the sky above, in Chaucer.^[2]
• c. 1504 – figurative, a realm or sphere.^[2]
• 1532 – the spelling hemisphere.^[3]
• 1555 – either half of the earth.^[2][5]
• 1585 – half of a sphere.^[2]
• 1706 – a map of half the globe.^[2]
• 1804 – either half of the brain.^[2][5]
• 1815 – Magdeburg hemispheres.^[2]

Meanings

Noun

1. Half of a sphere, formed by a plane through its centre.^[9][2]
2. Half of the earth, as divided by the equator into the Northern and Southern Hemispheres, or by a meridian into the Eastern and Western Hemispheres: Winter comes in July in the southern hemisphere.^[9][2]
3. Either half of the celestial sphere, divided by the celestial equator, the ecliptic or the horizon.^[9][7][2]
4. A map or projection of half of the globe or of the sky.^[9][7][2]
5. Either half of the cerebrum of the brain; a cerebral hemisphere.^[9][2]
6. A realm or field of activity or thought.^[7][2]
7. (obsolete) The sky above the horizon.^[7][2]

Word family

• hemispheric
• hemispherically
• hemispherectomy
• hemispherical
• hemispheroid
• Eastern Hemisphere
• Magdeburg hemisphere
• Northern Hemisphere

Related words

• hemi-
• sphere
• semi-
• hemistich

References

1. ^ a b c d 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 t u v w x y z 27 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f g Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
4. ^ a b c Benson, Larry D., Glossarial Concordance to Middle English (Chaucer, Gower), Johns Hopkins University, github.com/jhu-digital-manuscripts/gcme
5. ^ a b c d e f g h i Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
7. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
8. ^ a b c Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
9. ^ a b c d e f Collins English Dictionary (2023), Glasgow: HarperCollins
10. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.