lon·​gi·​tude | \ ˈlän-jə-ˌtüd How to pronounce longitude (audio) , -ˌtyüd, British also ˈläŋ-gə- \

Definition of longitude

1a : angular distance measured on a great circle of reference from the intersection of the adopted zero meridian with this reference circle to the similar intersection of the meridian passing through the object
b : the arc or portion of the earth's equator intersected between the meridian of a given place and the prime meridian and expressed either in degrees or in time
2 archaic : long duration

Illustration of longitude

Illustration of longitude

longitude 1a: hemisphere marked with meridians of longitude

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Did You Know?

The imaginary (but very important) lines of longitude run from the North Pole to the South Pole. Each is identified by the number of degrees it lies east or west of the so-called prime meridian in Greenwich, England (part of London). A circle is divided into 360°; so, for example, the longitude of the Egyptian city of Cairo is about 31°E—that is, about 31° east of London. The "long" sense of the root may be easier to see in some uses of the adjective longitudinal: A longitudinal study is a research study that follows its subjects over many long years, and a longitudinal engine is one that drives a crankshaft that runs lengthwise under a vehicle (as in rear-wheel-drive cars) rather than crosswise.

Examples of longitude in a Sentence

a map of the world showing lines of latitude and longitude calculating the longitudes of different places The regions are on roughly the same longitude.
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Recent Examples on the Web The outermost ring of panels may translate to JPL’s latitude and longitude. Theresa Machemer, Smithsonian Magazine, "Perseverance Rover Shares Its First Video and Audio of Mars," 23 Feb. 2021 That's the approximate time on your clock, regardless of your longitude. Todd Nelson, Star Tribune, "Gradual Warming Trend Continues. 30s by Sunday?," 15 Feb. 2021 Later, the hacker shared a tweet containing a screenshot of metadata included in the upload with location data such as GPS longitude and GPS latitude. Kelly Tyko, USA TODAY, "Parler data breach: Archived posts from Capitol riots could reveal platform's role in the insurrection," 12 Jan. 2021 The large image shows storm surge across the region, mapped onto longitude and latitude. Mark Fischetti, Scientific American, "Hurricane Sandy Animations Could Improve Flood Forecasts," 29 Oct. 2013 With the fix, the Application Programming Interface only provides the city, state and zip code of posts, as well as approximate latitude and longitude coordinates. Coral Murphy, USA TODAY, "Ring's Neighbors app exposed users' home addresses, locations due to security flaw," 15 Jan. 2021 For the Bristol Bay project, Putman is using a high-resolution magnetic model for 304,000 latitude/longitude points over the past 20 years, looking at the impact of mining activity on fluctuations in local geomagnetic fields. Anchorage Daily News, "Privately funded study to examine role of regional magnetism in migration of Bristol Bay salmon," 12 Jan. 2021 This list of 2,586 latitude and longitude coordinates, each about a hundred yards from the one before it, would lead the robots from the Slash X Cafe in Barstow, California, to the finish line in Primm, Nevada, 142 miles away. Alex Davies, Wired, "The Autonomous-Car Chaos of the 2004 Darpa Grand Challenge," 6 Jan. 2021 Since a line crosses just once through any particular latitude or longitude, its solution is just one value. Caroline Delbert, Popular Mechanics, "Mathematician Finds Easier Way to Solve Quadratic Equations," 8 Dec. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'longitude.' 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 longitude

15th century, in the meaning defined at sense 1a

History and Etymology for longitude

Middle English, from Latin longitudin-, longitudo, from longus

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Learn More about longitude

Time Traveler for longitude

Time Traveler

The first known use of longitude was in the 15th century

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Statistics for longitude

Last Updated

1 Mar 2021

Cite this Entry

“Longitude.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/longitude. Accessed 5 Mar. 2021.

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More Definitions for longitude



English Language Learners Definition of longitude

: distance measured in degrees east or west from an imaginary line (called the prime meridian) that goes from the North Pole to the South Pole and that passes through Greenwich, England
: an imaginary line that circles the Earth at a particular longitude


lon·​gi·​tude | \ ˈlän-jə-ˌtüd How to pronounce longitude (audio) , -ˌtyüd \

Kids Definition of longitude

: distance measured in degrees east or west of an imaginary line that runs from the north pole to the south pole and passes through Greenwich, England

More from Merriam-Webster on longitude

Nglish: Translation of longitude for Spanish Speakers

Britannica.com: Encyclopedia article about longitude

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