Generally something that establishes or serves as a pattern or gauge, such as a thin metal plate with a cut pattern that is used as a guide in making something accurately in woodworking. In our discourse this normally refers to a computer document or file having a preset format that is used as a starting point for a particular application so that the format does not have to be recreated each time it is used. This could be a loan amortization template for a spreadsheet program; a memorandum template for a word processing program, a mixer configuration for Pro Tools, a MIDI setup for sequencing software, a basic two zone layer for a keyboard controller, or any of dozens of other applications. Anytime one is working with a device that is programmable and has many different parameters templates can save a lot of time configuring new sessions, mixes, setups, and so on.
An overlay that fits over all or part of a keyboard or other type of hardware control panel and has labels describing the functions of each key within a particular application is also known as a template.