Geocentric longitude

Longitude Lon"gi*tude, n. [F., fr. L. longitudo, fr. longus long.] 1. Length; measure or distance along the longest line; -- distinguished from {breadth} or {thickness}; as, the longitude of a room; rare now, except in a humorous sense. --Sir H. Wotton. [1913 Webster]

The longitude of their cloaks. --Sir. W. Scott. [1913 Webster]

Mine [shadow] spindling into longitude immense. --Cowper. [1913 Webster]

2. (Geog.) The arc or portion of the equator intersected between the meridian of a given place and the meridian of some other place from which longitude is reckoned, as from Greenwich, England, or sometimes from the capital of a country, as from Washington or Paris. The longitude of a place is expressed either in degrees or in time; as, that of New York is 74[deg] or 4 h. 56 min. west of Greenwich. [1913 Webster]

3. (Astron.) The distance in degrees, reckoned from the vernal equinox, on the ecliptic, to a circle at right angles to the ecliptic passing through the heavenly body whose longitude is designated; as, the longitude of Capella is 79[deg]. [1913 Webster]

{Geocentric longitude} (Astron.), the longitude of a heavenly body as seen from the earth.

{Heliocentric longitude}, the longitude of a heavenly body, as seen from the sun's center.

{Longitude stars}, certain stars whose position is known, and the data in regard to which are used in observations for finding the longitude, as by lunar distances. [1913 Webster]