Unusually snug tent head of Winchester may stand for? (8)
I believe the answer is:
tungsten
'head of winchester may stand for?' is the definition.
I can't tell whether this defines the answer.
'unusually snug tent' is the wordplay.
'unusually' indicates an anagram.
'snug'+'tent'='snugtent'
'snugtent' with letters rearranged gives 'TUNGSTEN'.
(Other definitions for tungsten that I've seen before include "Hard metal used in lamps etc" , "Steel-grey metal" , "Light-filament element" , "Very hard metal, used in light bulbs" , "Element used in steels" .)