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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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 That all of these features float alongside a domed skeleton of latitude and longitude lines and still make room for a flying tourbillon in a circular aperture at 6 o’clock is a testament to the watchmaker’s twin mastery of art and mechanics. Paige Reddinger, Robb Report, 30 Mar. 2022 Peiresc helped to solve the mystery of longitude by writing innumerable letters to correspondents all over Europe and soliciting information from them about the relative positions of the sun, moon and stars on certain dates. Barton Swaim, WSJ, 4 Feb. 2022 Low pressure systems tracking over this spot -- the intersection of 40 degrees North latitude and 70 degrees West longitude -- are known for being significant in the Northeast, often bringing large amounts of snowfall to the area. Allison Chinchar And Monica Garrett, CNN, 25 Jan. 2022 The La Palma grid pattern represents the intersections of lines of latitude and longitude where earthquake records are being grouped as the user zooms to those limits. Kate S. Petersen, USA TODAY, 8 Nov. 2021 Navigation requires determining a ship’s location in latitude and longitude. Daniella Mccahey, The Conversation, 10 Mar. 2022 In the 1600’s maritime navies suffered incredible losses of life and ships due to the inability to find longitude at sea. Roberta Naas, Forbes, 20 Oct. 2021 Prime Meridian has stood as the mainstay for all timekeeping and longitude designations for hundreds of years. Roberta Naas, Forbes, 20 Oct. 2021 Located in Milot, Haiti, Sans-Souci does not share this latitude and longitude, which is that of the Watershed. Marlene Daut, Harper's BAZAAR, 8 Oct. 2021 See More

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.

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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Time Traveler for longitude

Time Traveler

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

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Dictionary Entries Near longitude

Long Island Sound


longitude by account

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Statistics for longitude

Last Updated

6 Apr 2022

Cite this Entry

“Longitude.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/longitude. Accessed 19 May. 2022.

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More Definitions for 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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