That which turns a description into something perceivable. It adds no meaning; it makes existing meaning visible.
An agent noun built on render, from Latin reddere (to give back): red- (back) + dare (to give); a renderer is named for the giving-back, the act of making an existing meaning visible.
That which turns a description into something perceivable. It adds no meaning of its own — it only makes meaning that already existed visible.