A (usually small) piece of software that adds features to or enhances a larger piece of software. The idea behind plug-ins is that a small piece of software is loaded into memory by the larger program, adding a new feature, and that users need only install the few plug-ins that they need, out of a much larger pool of possibilities. An example is the set of additional tools and effects available to Photoshop image editor in the Plug-ins folder. There are many plug-ins for Netscape Navigator such as Shockwave player that give the browser special capabilities, especially for multimedia websites.