Slid round covers (4)
I believe the answer is:
lids
'covers' is the definition.
(lid is a kind of cover)
'slid round' is the wordplay.
'round' is an anagram indicator.
'slid' anagrammed gives 'LIDS'.
(Other definitions for lids that I've seen before include "Eye covers" , "Movable tops or covers" , "Covers for opening and closing" .)