Any imaginary line perpendicular to the equator and part of a great circle passing through the North Pole and South Pole
Geographic distance east or west of the prime meridian expressed in degrees and minutes
Longitude is a coordinate that is used to specify positions on a sphere The longitude of a place is the distance of the place to the prime meridian, measured in degrees along a circle at a fixed distance to the poles of the sphere All places with the same longitude lie on a half-circle between the poles On Earth, the prime meridian of the common geographical coordinate system is the one passing through Greenwich in England In the sky, longitude is one of the coordinates used in the ecliptical and galactic coordinate systems The corresponding coordinate in the equatorial coordinate system is called right ascension The second coordinate needed to specify a position on a sphere is the latitude
The angular measurement of a point on the earth's surface, east or west of the prime meridian The prime meridian runs through Greenwich, England and is 0 degrees longitude Since measurements are made East and West, the maximum longitude value is 180 degrees Mathematically, longitudes are usually denoted as positive for easterly longitudes (e g , +71 degrees = 71 E), and negative for westerly longitudes (e g , -65 degrees = 65 W)
In general, an angular distance along a primary great circle from an adopted reference point On the Earth's surface, the angle between the Greenwich meridian (0o) and the meridian of a point on the Earth, measured eastward or westward from the former through 180o and labelled E or W to indicate the direction of measurement
(Meridians of) Angular distance east or west on the earth's surface, measured from the prime meridian that is 0° and runs through Greenwich, England The International Date Line is 180°
an imaginary great circle on the surface of the earth passing through the north and south poles at right angles to the equator; "all points on the same meridian have the same longitude"
A measure of distance east and west of a line drawn between the North and South Poles and passing through the Royal Observatory at Greenwich, England
distance on the Earth (measured in degrees) east or west from a reference line, usually the line running between the poles passing through Greenwich, England
distance east or west on the earth's surface, measured as an arc of the equator (in degrees up to 180o or by the difference in time) between the meridian passing through a particular place and a standard or prime meridian
Angular distance measured in degrees east or west of the prime meridian of Greenwich, England
Angular distance measured in degrees, minutes, and seconds 180 degrees east and west from the Prime Meridian, the imaginary north-south line through Greenwich, England