Radar antennae cover (6)
I believe the answer is:
radome
'radar antennae cover' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for radome that I've seen before include "Aircraft protective cover for radar equipment" , "Cover for microwave antennae" , "cover for electronic equipment" , "Radar antennae cover" , "Cover for rangefinder" .)