Definition - What does Virtual Studio Technology (VST) mean?
Virtual studio technology (VST) is a digital interface standard that is used to connect and integrate software audio effects, synthesizers and effect plugins with recording systems and audio editors. VST is basically a software emulation of hardware synthesizers, instruments and samplers, and often provides a custom user interface that mimics the original hardware down to knobs and switches. It provides recording engineers and musicians access to virtual versions of devices and equipment that might be otherwise too expensive or difficult to procure.
Techopedia explains Virtual Studio Technology (VST)
Virtual studio technology is a software emulation of various sound recording equipment and instruments; it makes use of digital signal processing in order to simulate specific equipment. VST often comes as a plugin for a digital audio workstation, providing it with the additional functionality desired.
There are many types of VST plugins, which can be mostly classified as instruments (VSTi) or effects. VSTi does exactly what its name implies, as it emulates different musical instruments so that the recording engineer or musician does not need to procure the specific instrument or find someone who can play it. Modern VST plugins provide their own custom GUI, but older ones tended to rely on the UI of the host software.