Though similar in purpose they measure different things. Gyroscopes determine orientation while accelerometers measure non-gravitational acceleration.
Inexpensive vibrating structure microelectromechanical systems (MEMS) gyroscopes have become widely available. These are packaged similarly to other integrated circuits and may provide either analog or digital outputs. In many cases, a single part includes gyroscopic sensors for multiple axes. Some parts incorporate multiple gyroscopes and accelerometers (or multiple-axis gyroscopes and accelerometers), to achieve output that has six full degrees of freedom. These units are called inertial measurement units, or IMUs.
Internally, MEMS gyroscopes use lithographically constructed versions of one or more of tuning forks, vibrating wheels, or resonant solids mechanisms of various designs.