lon·gi·tude | \ˈlän-jə-ˌtüd, -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

Keep scrolling for more

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.
See More

Recent Examples on the Web

The Bassatine News website, an online newsletter put out by Cairo’s Jewish community council, gives the cemetery’s exact longitude and latitude, which would have been useful if my phone had worked in Egypt. Michael David Lukas, New York Times, "From Cairo to Kolkata, Traces of a Vibrant Jewish Past," 8 June 2018 One of those sources said the longitude and latitude returned by Xiao’s queries came within 100 yards of their then-current location. Dan Goodin, Ars Technica, "Website leaked real-time location of most US cell phones to almost anyone," 17 May 2018 The lines that are already on the basketball are like lines of longitude. Rhett Allain, WIRED, "Figure Out Where You Are With Nothing But a Watch and Protractor," 3 May 2018 The data include estimates of the latitude and longitude of each named storm's center at six-hour intervals. Anchorage Daily News, "Hurricanes are moving more slowly. That makes them more dangerous.," 6 June 2018 Working with Frank, Turton and Beneduce determined the photo’s exact location using the longitude and latitude from the images and even enlisted the help of an oceanographer to determine just how the sign traveled so far. Char Adams, PEOPLE.com, "N.J. Realty Sign Lost in Hurricane Sandy Found in France 5 Years Later: 'I Couldn't Believe It'," 1 June 2018 The interactive site also shows rotor diameter and hub height, turbine models and their positions by latitude and longitude. Jim Efstathiou Jr, Bloomberg.com, "A Wind Lover's Dream: All 57,636 U.S. Wind Turbines on One Map," 20 Apr. 2018 This time difference is essentially your longitude. Rhett Allain, WIRED, "Figure Out Where You Are With Nothing But a Watch and Protractor," 3 May 2018 But as one gets close to the poles, lines of longitude converge and the system breaks down. NBC News, "Einstein made his share of errors. Here are three of the biggest," 14 Mar. 2018

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.

See More

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

Keep scrolling for more

Learn More about longitude

Statistics for longitude

Last Updated

17 Oct 2018

Look-up Popularity

Time Traveler for longitude

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

See more words from the same century

Keep scrolling for more

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, -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

Keep scrolling for more

Comments on longitude

What made you want to look up longitude? Please tell us where you read or heard it (including the quote, if possible).


a state of commotion or excitement

Get Word of the Day daily email!

Test Your Vocabulary

Words from Greek and Roman Mythology Quiz

  • the-triumph-of-venus-by-alessandro-magnasco
  • Boreal comes from the name of the ancient Greek god of which wind?
Spell It

Can you spell these 10 commonly misspelled words?

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!