けいど経度keido
1.
A measure of how far east or west a point on the Earth's surface is from a reference line known as the prime meridian, typically established at Greenwich, England, represented in degrees, minutes, and seconds.
2.
A coordinate that, together with latitude, specifies the exact location on the Earth, calculated based on the angle formed between the prime meridian and the meridian that passes through the specific point in question.
Example:
赤道における経度1度当たりの長さ。