A shade is when a color remains its original hue but has been darkened. Shading darkens the color. Typically, only black is added to the pure color or hue to give it shade. There is no white or gray added. You can also add black to a combination of colors to create a shade. It is not specifically for pure colors.
Scalable Vector Graphics (SVG) is an XML-based vector image format for defining two-dimensional graphics, having support for interactivity and animation.
SVG images are defined in a vector graphics format and stored in XML text files. SVG images can thus be scaled in size without loss of quality, and SVG files can be searched, indexed, scripted, and compressed. The XML text files can be created and edited with text editors or vector graphics editors, and are rendered by the most-used web browsers. source