n.
   - a large, impressive house.
 - 
(mansion block)
 Brit. a large block of flats.
 - (in names) a terrace or mansion block:
 Carlyle Mansions.
 
 
  Etymology
  ME (denoting the chief residence of a lord): via OFr. from L. mansio(n-) ‘place where someone stays’, from manere ‘remain’.