The Collaborative International Dictionary of English v.0.48:

Rapid \Rap"id\, Rapids \Rap"ids\(r[a^]p"[i^]dz), n. [Cf. F.
   rapide. See Rapid, a.]
   The part of a river where the current moves with great
   swiftness, but without actual waterfall or cascade; sometimes
   called whitewater; -- usually used in the plural; as, the
   Lachine rapids in the St. Lawrence. For boaters on the river,
   it is a place that can be hazardous, with danger of capsizing
   or crashing into large rocks.
   [1913 Webster +PJC]

         Row, brothers, row, the stream runs fast,
         The rapids are near, and the daylight's past. --Moore.
   [1913 Webster] Rapid-fire

The Collaborative International Dictionary of English v.0.48:

White-water \White"-wa`ter\, n. (Far.)
   A dangerous disease of sheep.
   [1913 Webster]

WordNet (r) 3.0 (2006):

whitewater
    n 1: frothy water as in rapids or waterfalls [syn: white
         water, whitewater]

U.S. Gazetteer Places (2000):

Whitewater, WI -- U.S. city in Wisconsin
   Population (2000):    13437
   Housing Units (2000): 4340
   Land area (2000):     6.985740 sq. miles (18.092984 sq. km)
   Water area (2000):    0.292918 sq. miles (0.758655 sq. km)
   Total area (2000):    7.278658 sq. miles (18.851639 sq. km)
   FIPS code:            86925
   Located within:       Wisconsin (WI), FIPS 55
   Location:             42.834950 N, 88.736119 W
   ZIP Codes (1990):     53190
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Whitewater, WI
    Whitewater


U.S. Gazetteer Places (2000):

Whitewater, MO -- U.S. town in Missouri
   Population (2000):    113
   Housing Units (2000): 60
   Land area (2000):     0.200341 sq. miles (0.518880 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.200341 sq. miles (0.518880 sq. km)
   FIPS code:            79612
   Located within:       Missouri (MO), FIPS 29
   Location:             37.237021 N, 89.797465 W
   ZIP Codes (1990):     63785
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Whitewater, MO
    Whitewater


U.S. Gazetteer Places (2000):

Whitewater, IN -- U.S. town in Indiana
   Population (2000):    78
   Housing Units (2000): 32
   Land area (2000):     0.079919 sq. miles (0.206990 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.079919 sq. miles (0.206990 sq. km)
   FIPS code:            84086
   Located within:       Indiana (IN), FIPS 18
   Location:             39.943503 N, 84.830332 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Whitewater, IN
    Whitewater


U.S. Gazetteer Places (2000):

Whitewater, KS -- U.S. city in Kansas
   Population (2000):    653
   Housing Units (2000): 255
   Land area (2000):     0.330471 sq. miles (0.855916 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.330471 sq. miles (0.855916 sq. km)
   FIPS code:            78050
   Located within:       Kansas (KS), FIPS 20
   Location:             37.963178 N, 97.147435 W
   ZIP Codes (1990):     67154
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Whitewater, KS
    Whitewater