A modern type of regulator, which features a reference, high-gain amplifier, temperature-compensated voltage sensing resistors and transistors as well as a pass element is commonly referred to as a:

Despite the complex internal circuitry described—including a high-gain amplifier, reference voltage, and temperature-compensated sensing resistors—this entire regulator circuit is manufactured as a single integrated circuit (IC). The most common and convenient form of this IC is the three-terminal regulator, which requires only an input pin, an output pin, and a common ground pin. Familiar examples include the 78xx and 79xx series of voltage regulators. The distractors mentioning six, nine, or twenty-four pins are incorrect because the genius of this modern component is its simplicity for the end user, requiring only three terminals to function.