Variety, fit for all to see, survived over in valley (10)
I believe the answer is:
vaudeville
'variety' is the definition.
(vaudeville is a kind of variety)
'fit for all to see survived over in valley' is the wordplay.
'fit for all to see' becomes 'U' (Universal DVD certificate).
'survived' becomes 'lived' ('live' can be a synonym of 'survive').
'over' says the letters should be written in reverse.
'in' is an insertion indicator.
'valley' becomes 'vale' (synonyms).
'lived' in reverse letter order is 'devil'.
'u'+'devil'='udevil'
'udevil' put within 'vale' is 'VAUDEVILLE'.
(Other definitions for vaudeville that I've seen before include "Variety entertainment" , "American music hall" , "Musical and comedy entertainment" , "theatrical entertainment" , "variety show" .)