Vehicle for travelling over snow (6)
I believe the answer is:
sledge
'vehicle for travelling over snow' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for sledge that I've seen before include "Vehicle mounted on runners" , "In the field, abuse" , "Vehicle for use in snow" , "Narrow cart with runners for travelling on snow" , "heavy tool" .)