Virtual Studio Technology - VST plugins

• Virtual Studio Technology (VST) is an interface for integrating software audio synthesizer and effect plugins with audio editors and hard-disk recording systems. VST and similar technologies use Digital Signal Processing to simulate traditional recording studio hardware with software.

• The VST plugin standard is the audio plugin standard created that allow any third party developers to create VST plugins for use within VST host applications. VST requires separate installations for Windows/Mac/Linux. The majority of VST plugins are available for Windows due to both Apple's proprietary Audio Unit software for OS X and the lack of information and patent encumbrances that make development difficult for Linux platforms.

Check here for vst plugins