Meaning of LINE OF LONGITUDE

WordNet Dictionary
	Definition:		[n]  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"
	Synonyms:		longitude, meridian
	See Also:		date line, dateline, great circle, International Date Line, magnetic meridian, observer's meridian, prime meridian