01 n. Length; measure or distance along the longest line; -- distinguished from breadth or thickness; as, the longitude of a room; rare now, exce…
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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.“The longitude of their cloaks.” — Sir. W. Scott.“Mine [shadow] spindling into longitude immense.” — Cowper.
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2.
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° or 4 h. 56 min. west of Greenwich.(Geog.)
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3.
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°.(Astron.)
Phrases & compounds
Geocentric longitude —
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.