Vector graphics are a representation of a representation based on a description of the coordinates and shapes that constitute the image. Compared to bitmap graphics, vector graphics are scalable, in that they can be rendered to different sizes (or resolutions of pixels) as needed.
SVG (or Scalable Vector Graphics) is a free XML-based format for vector graphics, and is part of HTML5. Adobe Illustrator and Flash are examples of propriety applications and formats of vector graphics. Inkscape is a popular free software vector graphics editor.
See also Sketchpad