Also found in: Dictionary, Thesaurus, Medical, Legal, Acronyms, Encyclopedia, Wikipedia.
Related to power down: power outage
1. To cease functioning or operating by disconnecting from a power source. To avoid damaging the screen, these new LED televisions power down automatically after half an hour if they are not being used. The hackers were able to rewrite the security system's code so that it powered down without sending an alert or raising an alarm.
2. To cause something, especially a computer or computer system, to cease functioning or operating by prompting it to disconnect from a power source. In this usage, a noun or pronoun can be used between "power" and "down." Please be sure to power down your computer before you leave the office. It turns out that a technician powered the entire defense network down by mistake, leaving us wide open to cyber attacks for over an hour.
1. To stop the operation of something, especially when a special process is required: The engineers powered down the generator to repair the wires. After we were finished with the computer, we powered it down.
2. To stop operating, especially when a special process is required: The computer powers down automatically if not used for four hours.