The Collaborative International Dictionary of English v.0.48:

Manor \Man"or\, n. [OE. maner, OF. maneir habitation, village,
   F. manoir manor, prop. the OF. inf. maneir to stay, remain,
   dwell, L. manere, and so called because it was the permanent
   residence of the lord and of his tenants. See Mansion, and
   cf. Remain.]
   1. (Eng. Law) The land belonging to a lord or nobleman, or so
      much land as a lord or great personage kept in his own
      hands, for the use and subsistence of his family.
      [1913 Webster]

            My manors, rents, revenues, l forego. --Shak.
      [1913 Webster]

   Note: In these days, a manor rather signifies the
         jurisdiction and royalty incorporeal, than the land or
         site, for a man may have a manor in gross, as the law
         terms it, that is, the right and interest of a
         court-baron, with the perquisites thereto belonging.
         [1913 Webster]

   2. (American Law) A tract of land occupied by tenants who pay
      a free-farm rent to the proprietor, sometimes in kind, and
      sometimes by performing certain stipulated services.
      --Burrill.
      [1913 Webster]

   Manor house, or Manor seat, the house belonging to a
      manor; the house of the lord of the manor; a manse.
      [1913 Webster]

WordNet (r) 3.0 (2006):

manor house
    n 1: the mansion of a lord or wealthy person [syn: manor,
         manor house]

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "manor house":
   Dymaxion house, White House, adobe house, building, casa,
   cliff dwelling, consulate, country house, country seat, dacha,
   deanery, dwelling house, edifice, embassy, erection, fabric, farm,
   farmhouse, hall, house, houseboat, lake dwelling, living machine,
   lodge, manse, parsonage, penthouse, prefabricated house,
   presidential palace, ranch house, rectory, roof, skyscraper,
   sod house, split-level, structure, town house, vicarage