1. A representation of the world using points, lines, and polygons. Vector models are useful for storing data that has discrete boundaries, such as country borders, land parcels, and streets.
2. In vector data the features are recorded one by one, with shape being defined by the numerical values of the pairs of xy coordinates. A point is defined by a single pair of coordinate values. A line is defined by a sequence of coordinate pairs defining the points through which the line is drawn. An area is defined in a similar way, only with the first and last points joined to make a complete enclosure.
Geographic information system
http://support.esri.com/other-resources/gis-dictionary/term/vector%20data%20model (1.); https://www.ordnancesurvey.co.uk/support/understanding-gis/raster-vector.html (2.)
Author: Thomas D.