The Collaborative International Dictionary of English v.0.48:

Colter \Col"ter\, n. [AS. culter, fr. L. culter plowshare,
   knife. Cf. Cutlass.]
   A knife or cutter, attached to the beam of a plow to cut the
   sward, in advance of the plowshare and moldboard. [Written
   also coulter.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Coulter \Coul"ter\ (k[=o]l"t[~e]r), n.
   Same as Colter.
   [1913 Webster]

WordNet (r) 3.0 (2006):

coulter
    n 1: a sharp steel wedge that precedes the plow and cuts
         vertically through the soil [syn: colter, coulter]

Easton's 1897 Bible Dictionary:

Coulter
   (1 Sam. 13:20, 21), an agricultural instrument, elsewhere called
   "ploughshare" (Isa. 2:4; Micah 4:3; Joel 3:10). It was the
   facing-piece of a plough, analogous to the modern coulter.


U.S. Gazetteer Places (2000):

Coulter, IA -- U.S. city in Iowa
   Population (2000):    262
   Housing Units (2000): 118
   Land area (2000):     2.453894 sq. miles (6.355556 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    2.453894 sq. miles (6.355556 sq. km)
   FIPS code:            16815
   Located within:       Iowa (IA), FIPS 19
   Location:             42.734311 N, 93.369173 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Coulter, IA
    Coulter