Scalable Vector Graphics (SVG) is an XML-based vector image format for two-dimensional graphics with support for interactivity and animation. The SVG specification is an open standard developed by the World Wide Web Consortium (W3C) since 1999. SVG images and their behaviors are defined in XML text files.
You know all the JPG, PNG, BMP, TIFF and other common bitmap graphic formats. What they have in common is that they carry the visual information encoded as two dimensional array of dots (pixels), where every pixel has information about the color on exactly this spot. So bitmap is in fact like impressionistic painting, which is composed of visible dots.
On the other hand, in vector image, the visual information is encoded in more formal way by geometric constructs like points, lines, polygons, curves, planes, and operations with them.
There is a myth, that vector graphic is harder to produce. This believe comes from dark ages, when there were only few commercial cumbersome editors. But, with Inkscape, such bear like in the example can be created in minutes! Vector graphics has numerous other advantages: