Gear placed around loch that covers a lot of Scotland (4)
I believe the answer is:
kilt
'that covers a lot of scotland' is the definition.
(Scottish item of clothing)
'gear placed around loch' is the wordplay.
'gear' becomes 'kit' (kit is a kind of gear).
'placed around' indicates putting letters inside.
'loch' becomes 'l'.
'kit' enclosing 'l' is 'KILT'.
(Other definitions for kilt that I've seen before include "Highland garb" , "Scotsman's attire" , "Scottish garb" , "Scots dress" , "Tartan clothing item" .)