Tractor-trailer (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
semi
'tractor-trailer' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for semi that I've seen before include "Common type of house" , "House sharing a wall" , "Co-joined house" , "Residence" , "A whole house (or half?)" .)