A micro servo is a small servo. The term can be used to describe
any servo that is smaller than a "typical" servo. For example a
servo that is about 1.5" x 1.5" x 0.5" would probably be called a
micro servo. Most servos use the same signals and voltages, so
usually a micro servo can be plugged into any servo controller or
radio receiver that a regular servo can be plugged into.