Giant crest ruined by photon deflection (10)
I believe the answer is:
scattering
'photon deflection' is the definition.
The answer and definition can be both related to natural events as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'giant crest ruined' is the wordplay.
'ruined' is an anagram indicator.
'giant'+'crest'='giantcrest'
'giantcrest' anagrammed gives 'SCATTERING'.
'by' is the link.
Can you help me to learn more?
(Other definitions for scattering that I've seen before include "Throwing in various directions" , "Strewing" .)