longitude

noun

lon·​gi·​tude ˈlän-jə-ˌtüd 

-ˌtyüd,

 British also  ˈläŋ-gə-

1

a

: 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

• 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

This certification resonated with British customers who understood that accurate timekeeping—the solution to the long-standing problem of navigating longitude—had empowered the British Empire to dominate the seas in both combat and commerce. —Allen Farmelo, Robb Report, 11 May 2024

The great scientific problem of Williams’ day was determining longitude while at sea. —Yaakov Zinberg, Smithsonian Magazine, 4 Apr. 2024

Word History

Etymology

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

First Known Use

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

Kids Definition

longitude

noun

lon·​gi·​tude ˈlän-jə-ˌt(y)üd 

: 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