A minicomputer is a type of computer that possesses most of the features and capabilities of a large computer but is smaller in physical size.
A minicomputer fills the space between the mainframe and microcomputer, and is smaller than the former but larger than the latter. Minicomputers are mainly used as small or midrange servers operating business and scientific applications. However, the use of the term minicomputer has diminished and has merged with servers.
A minicomputer may also be called a mid-range computer.
What is a Minicomputer? - Definition from Techopedia