STL, an abbreviation for stereolithography, is an interchangeable file format that represents 3-dimensional surface geometry. The file format finds its usage in several fields such as rapid prototyping, 3D printing, and computer-aided manufacturing. It represents a surface as a series of small triangles, known as facets, where each facet is described by a perpendicular direction and three points representing the vertices of the triangle.
SVG files are Scalable Vector Graphics Files that use XML based text format for describing the appearance of image. The word Scalable refers to the fact that the SVG can be scaled to different sizes without losing any quality. Text based description of such files make them independent of resolution. It is one of the mostly used format for building website and print graphics in order to achieve scalability.
You can also convert STL into many other file formats. Please see the complete list below.