Audio's partner (5)
I believe the answer is:
video
'audio's partner' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for video that I've seen before include "Recorded film cassette" , "Relating to televised images" , "Visual element of television" , "Recording tape for visual images" , "Who killed the radio star? (5)" .)