The power supply unit (PSU) is an essential component of a computer that provides electric power to different parts of the machine. There are several synonyms for this term, including power brick, power adapter, power pack, and power converter. The power brick refers to an external power supply unit used to power electronic devices. The power adapter, on the other hand, is a device that converts AC power to DC power for other devices' power input. Power pack is another synonym for power supply unit, referring to a portable battery or battery pack used to recharge electronic devices, especially smartphones and tablets. Lastly, power converter refers to a device that converts one form of electrical energy into another.