1. genetics a succession of descendants from an individual, e.g., a family or race —note breeding crosses are made within lines and production crosses among lines, resulting in no inbreeding in the production population 2. GIS a set of ordered coordinates representing the shape of a geographic entity too narrow to be displayed as an area, e.g., contours, street centerlines, and streams —note a line begins and ends with a node 3. GIS a line on a map, e.g., a neatline —see stringThis definition last updated 07/12/2008