The Collaborative International Dictionary of English v.0.48:

Whereabout \Where"a*bout`\, Whereabouts \Where"a*bouts`\, n.
   The place where a person or thing is; as, they did not know
   his whereabouts. --Shak.
   [1913 Webster]

         A puzzling notice of thy whereabout.     --Wordsworth.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Whereabout \Where"a*bout`\, Whereabouts \Where"a*bouts`\, adv.
   [1913 Webster]
   1. About where; near what or which place; -- used
      interrogatively and relatively; as, whereabouts did you
      meet him?
      [1913 Webster]

   Note: In this sense, whereabouts is the common form.
         [1913 Webster]

   2. Concerning which; about which. "The object whereabout they
      are conversant." --Hooker.
      [1913 Webster]
      [1913 Webster] Whereabout

WordNet (r) 3.0 (2006):

whereabouts
    n 1: the general location where something is; "I questioned him
         about his whereabouts on the night of the crime"

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "whereabouts":
   abode, area, bearings, bench mark, district, emplacement, hole,
   in what place, in which place, latitude and longitude, lieu,
   locale, locality, location, locus, pinpoint, place, placement,
   point, position, region, site, situation, situs, spot, stead,
   where, whereabout, whither