The Collaborative International Dictionary of English v.0.48:

Kilowatt hour \Kil"o*watt` hour\ (Elec.)
   A unit of work or energy equal to that done by one kilowatt
   acting for one hour; -- approximately equal to 1.34
   horse-power hour.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

kilowatt hour
    n 1: a unit of energy equal to the work done by a power of 1000
         watts operating for one hour [syn: kilowatt hour, kW-
         hr, Board of Trade unit, B.T.U.]

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "kilowatt hour":
   abampere, abcoulomb, abfarad, abhenry, abohm, abvolt, ampere,
   ampere-foot, ampere-hour, ampere-minute, atomerg, calorie, coulomb,
   dinamode, dyne, energid, erg, farad, foot-pound, henry,
   horsepower-hour, horsepower-year, joule, kilogram-meter,
   kilovolt-ampere, kilowatt, megacoulomb, megavolt, megawatt, megohm,
   mho, microhenry, micromho, micromicrofarad, microvolt, microwatt,
   milliampere, millihenry, millivolt, ohm, ohm-mile, photon,
   picofarad, quantum, statampere, statcoulomb, statfarad, statvolt,
   volt, volt-coulomb, volt-second, watt, watt-hour