Concerning endless current cycle and energy reappearance (10)
I believe the answer is:
recurrence
'reappearance' is the definition.
(thesaurus)
'concerning endless current cycle and energy' is the wordplay.
'concerning' becomes 'rec' (I can't explain this - if you can you should give a lot more credence to this answer).
'endless' means to remove the last letter.
'cycle' indicates an anagram.
'and' says to put letters next to each other.
'energy' becomes 'e' (physics symbol as in E=mce).
'current' with its final letter taken off is 'curren'.
'curren' anagrammed gives 'urrenc'.
'rec'+'urrenc'+'e'='RECURRENCE'
Can you help me to learn more?
(Another definition for recurrence that I've seen is " Repetition".)