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

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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

Did You Know?

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 And this is carried out by one of the most violent, brutal, pro-American, and American-supported regimes in the hemisphere. Jon Blistein, Rolling Stone, "‘Blowback’ Podcast Tackles America’s Meddling in the Cuban Revolution," 19 Apr. 2021 Named by Christopher Columbus, who first sighted it on his second voyage to the hemisphere, in 1493, Dominica was colonized by the French and then traded back and forth between France and England across the 18th century. Michael Verdon, Robb Report, "How the Lush Caribbean Island of Dominica Became a Superyacht Haven," 18 Apr. 2021 There is also the deteriorating situation in the Northern Triangle nations in this hemisphere that has led to more migrants on the US southern border. BostonGlobe.com, "Obama talked about a ‘pivot to Asia.’ Biden is actually doing it," 16 Apr. 2021 Russia has sold more than $9 billion worth of military equipment since 2008 and conducted security training in 17 countries across the hemisphere. Abraham Mahshie, Washington Examiner, "US policies have failed to nudge Venezuelan military away from Maduro," 19 Mar. 2021 Some previous scientific papers had claimed that dolphins show strong rightward behavioral asymmetries, similar to human right-handedness, and therefore had a left-hemisphere specialization for action. Kelly Jaakkola, Scientific American, "Are Dolphins Right-Handed or Left-Handed?," 21 Feb. 2021 But as one Texas Democratic US Representative wrote in the New York Times, there might be pressure for Biden to pivot back to this hemisphere and try to deal with the underlying issues that force people to flee to the United States. BostonGlobe.com, "The situation on the southern border is Biden’s first political crisis as president ― whether he wants to admit it or not," 24 Mar. 2021 New research shows the Pacific hemisphere is losing heat faster than the African hemisphere. Caroline Delbert, Popular Mechanics, "Why One Side of Earth Is Rapidly Getting Colder Than the Other," 15 Mar. 2021 Bora Bora happens to be one of the best places to view the Southern hemisphere sky. Sarah Sekula, USA TODAY, "Astrotourism: These resorts will have you seeing stars," 25 Mar. 2021

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.

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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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Time Traveler for hemisphere

Time Traveler

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

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Last Updated

3 May 2021

Cite this Entry

“Hemisphere.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hemisphere. Accessed 9 May. 2021.

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More Definitions for hemisphere



English Language Learners Definition of hemisphere

: a half of the Earth
: half of a sphere : half of a round object
technical : either of the two halves of the brain


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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