Phenomena in air enthralling men at Pole (7)
I believe the answer is:
auroras
'phenomena' is the definition.
Although both the answer and definition are plural nouns, I don't see how they can define each other.
'air enthralling men at pole' is the wordplay.
'air' becomes 'aura' (synonyms).
'enthralling' means one lot of letters goes inside another.
'men at' becomes 'ro' (I can't explain this - if you can you should give a lot more credence to this answer).
'pole' becomes 's' (abbreviation for South, as in South Pole).
'aura' enclosing 'ro' is 'aurora'.
'aurora'+'s'='AURORAS'
'in' is the link.
Can you help me to learn more?
(Other definitions for auroras that I've seen before include "Polar lights" , "orange colours" .)