lon·​gi·​tude ˈlän-jə-ˌtüd How to pronounce longitude (audio)
 British also  ˈläŋ-gə-
: 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
: 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
archaic : long duration

Illustration of longitude

Illustration of longitude
  • hemisphere marked with meridians of longitude

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.
Recent Examples on the Web Unfortunately, the technique can’t tell us the location’s longitude (east−west). Howard Lee, Ars Technica, 16 Aug. 2023 And adding a tourbillon to the Marine collection seems fitting, given that Breguet was made the official chronometer-maker to France’s Royal Navy in 1815, responsible for managing the calculation of longitude at sea. Carol Besler, Robb Report, 16 Oct. 2023 Duplicate sites that appeared in the U.S.G.S. and regional data sets were removed based on matching site numbers where available, and by matching latitude, longitude and well-depth combinations. Mira Rojanasakul, New York Times, 28 Aug. 2023 Streisand says that all of the homes photographed for the project were labeled using latitude and longitude, and not by names of the owners, except for her and four other celebrities’ houses. Rachel Desantis, Peoplemag, 7 Nov. 2023 Very few studies of this longitude have been completed, and none at this scale. Carolyn Barber, Fortune, 21 Aug. 2023 Steller sea lions are split into two subpopulations — eastern and western, divided at 144 degrees of longitude. Elizabeth Earl For Alaska Journal Of Commerce, Anchorage Daily News, 17 Aug. 2023 Meridional flow follows a pattern from north to south, or from south to north, along the Earth’s longitude line. Greg Garrison | , al, 17 July 2023 That availability changes depending on the region’s latitude and longitude. Katie Hill, Outdoor Life, 23 Aug. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'longitude.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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

First Known Use

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

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

Dictionary Entries Near longitude

Cite this Entry

“Longitude.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/longitude. Accessed 26 Feb. 2024.

Kids Definition


lon·​gi·​tude ˈlän-jə-ˌt(y)üd How to pronounce longitude (audio)
: distance measured by degrees or time east or west from the prime meridian
the longitude of New York is 74 degrees or about five hours west of Greenwich

More from Merriam-Webster on longitude

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