Foreign character records dancing lion (7)
I believe the answer is:
epsilon
'foreign character' is the definition.
(I've seen this before)
'records dancing lion' is the wordplay.
'records' becomes 'EPs' (EP is a type of record).
'dancing' indicates anagramming the letters.
'lion' anagrammed gives 'ilon'.
'eps'+'ilon'='EPSILON'
(Other definitions for epsilon that I've seen before include "small number mispronounced, almost completely the wrong way round" , "foreign letter" , "Fifth letter of the Greek alphabet" , "Fifth brightest star in a constellation" , "Foreign character" .)