Power cut (6)
'power cut' is the definition.
(an outage is a loss of power)
This is the entire clue.
(Other definitions for outage that I've seen before include "Power cut" , "time of no power" , "Gap in power supply" , "Temporary suspension of operation" , "When one lacks power" .)
'power cut' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for blackout that I've seen before include "Loss of light, consciousness, or information" , "Temporary loss of consciousness or electric power" , "Sudden lights-off" , "Momentary loss of consciousness" , "complete dark" .)