UN - Geographic Information Systems
A one-dimensional object. A geographic data type consisting of a series of x,y coordinates, where the first and last coordinates are called nodes and the intermediate coordinates are termed vertices. Also referred to as an arc or a chain. The part of a line between two intersections with other lines is called a line or arc segment.
United Nations, "Handbook on Geospatial Infrastructure in Support of Census Activities", Department of Economic and Social Affairs, Statistics Division, Studies in Methods, Series F No. 103, New York, 2009