The Collaborative International Dictionary of English v.0.48:

Grandfather \Grand"fa"ther\, n.
   A father's or mother's father; an ancestor immediately after
   the father or mother in lineal ascent.
   [1913 Webster]

   Grandfather longlegs. (Zool.) See Daddy longlegs.
      [1913 Webster]

WordNet (r) 3.0 (2006):

grandfather
    n 1: the father of your father or mother [syn: grandfather,
         gramps, granddad, grandad, granddaddy, grandpa]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "grandfather":
   Father Time, Methuselah, Nestor, Old Paar, centenarian, dotard,
   elder, gaffer, geezer, golden-ager, grampa, gramps, grandpa,
   grandsire, graybeard, great-grandfather, nonagenarian,
   octogenarian, old chap, old codger, old dog, old duffer,
   old geezer, old gent, old gentleman, old man, old party, old-timer,
   older, oldster, pantaloon, patriarch, presbyter, senior citizen,
   septuagenarian, sexagenarian, the quiet-voiced elders,
   venerable sir, veteran



Bouvier's Law Dictionary, Revised 6th Ed (1856):

GRANDFATHER, domestic relations. The father of one's father or mother. The
father's father is called the paternal grandfather; the mother's father is
the maternal grandfather.



U.S. Gazetteer Places (2000):

Grandfather, NC -- U.S. village in North Carolina
   Population (2000):    73
   Housing Units (2000): 377
   Land area (2000):     1.500982 sq. miles (3.887526 sq. km)
   Water area (2000):    0.043443 sq. miles (0.112517 sq. km)
   Total area (2000):    1.544425 sq. miles (4.000043 sq. km)
   FIPS code:            27320
   Located within:       North Carolina (NC), FIPS 37
   Location:             36.100525 N, 81.850153 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Grandfather, NC
    Grandfather