Single-board computer (SBC)
What is a single board computer?
A single-board computer, or SBC, is a complete computer built on a single circuit board, which includes processing units, memory, input/output (I/Os) and all other features required by a functional computer.
Single-board computers were made as demonstration or development systems, for educational systems, or for use as embedded computer controllers. This type of computer has become widely popular among makers as "hacker boards" have become affordable even for students and low-budget personal projects (especially since the $5 Raspberry Pi Zero board).
Some of the most popular applications are:
A more in-depth definition of "single board computer" can be found on on Wikipedia.