symbol

The symbol element defines a group of template elements that can be instantiated via a use element. By itself, this element is not rendered; it can have the following attributes:

Attribute	Description
id	Identifier of the symbol.
viewBox	A list of four (x y width height) coordinates that can each be separated by white space or a comma. This information specifies a rectangle in user space, which will be mapped to the bounds of the viewport of the use element.
preseveAspectRatio	Note  Only xMinyMin (uniform scaling) is supported.