What comes before the final house? (4)

I believe the answer is:
semi
'house?' is the definition.
(semi-detached house)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for semi that I've seen before include "One house of pair" , "important match" , "half would do!" , "Not quite the biggest tie" , "The last but one round" .)
