Description of power reflected in natural oscillations (5)
I believe the answer is:
solar
'description of power' is the definition.
(solar power is a type of power)
'reflected in natural oscillations' is the wordplay.
'reflected' shows that the letters should be reversed in order.
'in' indicates the answer is hidden within the clue.
'ralos' is hidden in the letters of 'natural oscillations'.
'ralos' back-to-front is 'SOLAR'.
(Other definitions for solar that I've seen before include "Concerning the sun" , "Powered by the sun" , "of heavenly body" , "Of or derived from the sun" , "Particular star's" .)