Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter lambda (λ). The term 'longitude' is also used to refer to the distance of a point east or west of the Prime Meridian, which is the reference line from which longitude is measured. The two words EXTENT and LENGTH are both 6 letters long and can be used to describe longitude. EXTENT refers to the range or scope of something, while LENGTH is the measure of something from end to end.