hemi·​sphere | \ ˈhe-mə-ˌsfir How to pronounce hemisphere (audio) \

Definition of hemisphere

1a : a half of the celestial sphere as divided into two halves by the horizon (see horizon sense 1b), the celestial equator, or the ecliptic
b : half of a spherical or roughly spherical body (such as a planet) specifically : the northern or southern half of the earth as divided by the equator (see equator sense 2) or the eastern or western half as divided by a meridian (see meridian sense 1a(2)) affected by the weather in the other hemisphere
c : the inhabitants of a hemisphere of the Earth
2 : an area of knowledge or activity : sphere, province a hemisphere of life heretofore unknown to us
3 : one of two half spheres (see sphere entry 1 sense 2a) formed by a plane (see plane entry 1 sense 2a) through the sphere's center : half of a round object
4 : a map or projection of a celestial hemisphere (see hemisphere sense 1a) or a terrestrial hemisphere (see hemisphere sense 1b)
5 : cerebral hemisphere an injury to the left hemisphere

Other Words from hemisphere

hemispheric \ ˌhe-​mə-​ˈsfir-​ik How to pronounce hemisphere (audio) , -​ˈsfer-​ \ or hemispherical \ ˌhe-​mə-​ˈsfir-​i-​kəl How to pronounce hemisphere (audio) , -​ˈsfer-​ \ adjective

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Hemisphere includes the prefix hemi-, meaning "half". The northern and southern hemispheres are divided by the equator, the circle halfway between Earth's two poles. The eastern and western hemispheres aren't divided so exactly, since there are no poles in the Earth's east-west dimension. Often the dividing line is said to be the "prime meridian"—the imaginary north-south line that runs through Greenwich, England, from which all longitude is calculated (itself being the 0° meridian). But for simplicity's sake, the eastern hemisphere is often said to include all of Europe, Africa, Australia, and Asia, while the western hemisphere contains North and South America and a great deal of ocean.

Examples of hemisphere in a Sentence

a tumor in the right cerebral hemisphere
Recent Examples on the Web Co-owner of Variety Wholesalers, a company whose more than 400 retail outlets include two Roses discount stores in Louisville, Pope has stocked her stable with some of the priciest horseflesh in the hemisphere. Tim Sullivan, The Courier-Journal, 3 May 2022 As was with rock and jazz, hip-hop and reggaetón, afrobeats is poised to be segregated from its struggling Black pioneers while white artists go on to pocket millions as the new face and purveyors—at least on this side of the hemisphere. Marjua Estevez, refinery29.com, 20 Jan. 2022 Activists pointed out that Honduras, which has one of the hemisphere’s highest murder rates, was by no means a safe country, but Trump was pleased. Jon Lee Anderson, The New Yorker, 8 Nov. 2021 The level is particularly remarkable at a moment of political and economic turmoil in the hemisphere, in which many leaders, from President Biden to the leaders of Argentina, Colombia and Brazil, have seen their poll numbers tank. Washington Post, 9 Apr. 2022 From the right, Doug Heye lent his expertise to the unfolding events, occasionally from a work trip in Mexico City and sometimes from some of the best restaurant seats in this hemisphere. Philip Elliott, Time, 12 Mar. 2022 The roughly golf ball-sized tumor grew in the womb, engulfing much of the right hemisphere of his brain. Angie Leventis Lourgos, chicagotribune.com, 19 Feb. 2022 Should the United States throw a lifeline to the worst tyrant in the Western hemisphere in order to undermine an even worse tyrant in Europe? Kevin D. Williamson, National Review, 8 Mar. 2022 The hold of this little sadist, Ortega, and his comrades over Nicaragua is one of the horrors of our hemisphere and our time. Nr Editors, National Review, 17 Mar. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'hemisphere.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of hemisphere

14th century, in the meaning defined at sense 1a

History and Etymology for hemisphere

Middle English hemispere, from Latin hemisphaerium, from Greek hēmisphairion, from hēmi- + sphairion, diminutive of sphaira sphere

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The first known use of hemisphere was in the 14th century

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Last Updated

15 May 2022

Cite this Entry

“Hemisphere.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hemisphere. Accessed 20 May. 2022.

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More Definitions for hemisphere


hemi·​sphere | \ ˈhe-mə-ˌsfir How to pronounce hemisphere (audio) \

Kids Definition of hemisphere

1 : one of the halves of the earth as divided by the equator or by a meridian
2 : a half of a sphere
3 : either the left or the right half of the cerebrum

Other Words from hemisphere

hemispheric \ ˌhem-​ə-​ˈsfir-​ik , -​ˈsfer-​ \ or hemispherical \ -​ˈsfir-​i-​kəl , -​ˈsfer-​ \ adjective


hemi·​sphere | \ -ˌsfi(ə)r How to pronounce hemisphere (audio) \

Medical Definition of hemisphere

: half of a spherical structure or organ: as
b : either of the two lobes of the cerebellum of which one projects laterally and posteriorly from each side of the vermis


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