SVG is a platform for two-dimensional graphics. It has two parts: an XML-based file format and a programming API for graphical applications. Just to enumerate some of the key features: shapes, text, and embedded raster graphics with many painting styles, scripting through languages such as ECMAScript and support for animation.
SVG is a vendor-neutral open standard that has important industry support. Companies like Adobe, Apple, IBM, and others have contributed to the W3C specification. Many documentation frameworks, including DocBook, have support for SVG by defining the graphics directly in the document.