Inkscape is an Open Source vector graphics editor, with capabilities similar to Illustrator, Freehand, CorelDraw, or Xara X using the open-standard Scalable Vector Graphics (SVG) file format. Inkscape's main goal is to create a powerful and convenient drawing tool fully compliant with XML, SVG, and CSS standards.
In contrast to raster (bitmap) graphics editors such as Photoshop or Gimp, Inkscape stores its graphics in a vector format. Vector graphics is a resolution-independent description of the actual shapes and objects that you see in the image. This description is then used to determine how to plot each line and curve at any resolution or zoom level.