The Collaborative International Dictionary of English v.0.48:

Plani- \Plan"i-\, Plano- \Plan"o-\ [L. planus. See Plane, a.]
   Combining forms signifying flat, level, plane; as
   planifolious, planimetry, plano-concave.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Plano- \Pla"no-\
   See Plani-.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Plano
    n 1: a city in northeastern Texas (suburb of Dallas)

U.S. Gazetteer Places (2000):

Plano, IL -- U.S. city in Illinois
   Population (2000):    5633
   Housing Units (2000): 1973
   Land area (2000):     3.513471 sq. miles (9.099849 sq. km)
   Water area (2000):    0.042408 sq. miles (0.109835 sq. km)
   Total area (2000):    3.555879 sq. miles (9.209684 sq. km)
   FIPS code:            60352
   Located within:       Illinois (IL), FIPS 17
   Location:             41.663137 N, 88.535987 W
   ZIP Codes (1990):     60545
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Plano, IL
    Plano


U.S. Gazetteer Places (2000):

Plano, IA -- U.S. city in Iowa
   Population (2000):    58
   Housing Units (2000): 40
   Land area (2000):     0.564606 sq. miles (1.462323 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.564606 sq. miles (1.462323 sq. km)
   FIPS code:            63345
   Located within:       Iowa (IA), FIPS 19
   Location:             40.756189 N, 93.046327 W
   ZIP Codes (1990):     52581
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Plano, IA
    Plano


U.S. Gazetteer Places (2000):

Plano, TX -- U.S. city in Texas
   Population (2000):    222030
   Housing Units (2000): 86078
   Land area (2000):     71.566021 sq. miles (185.355135 sq. km)
   Water area (2000):    0.062053 sq. miles (0.160716 sq. km)
   Total area (2000):    71.628074 sq. miles (185.515851 sq. km)
   FIPS code:            58016
   Located within:       Texas (TX), FIPS 48
   Location:             33.050374 N, 96.745935 W
   ZIP Codes (1990):     75023 75024 75025 75074 75075 75093
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Plano, TX
    Plano