Eight are moving in background (8)
I believe the answer is:
heritage
'background' is the definition.
(as in someone's national or ethnic background)
'eight are moving' is the wordplay.
'moving' is an anagram indicator.
'eight'+'are'='eightare'
'eightare' is an anagram of 'HERITAGE'.
'in' acts as a link.
(Other definitions for heritage that I've seen before include "Received culture and background" , "That which is passed down by tradition" , "Stuff handed down from the past" , "historical collection?" , "Patrimony" .)