The DICT Development Group

  taxi \tax"i\, n.
     1. same as taxicab.
        [PJC]
  
     2. any vehicle that carries passengers for a fare, as a water
        taxi.
        [PJC]

  taxicab \tax"i*cab\, n.
     an automobile with a professional driver which can be hired
     to carry passengers; -- also called a taxi, and informally
     called a cab or a hack. The driver of a taxicab is
     referred to as a cab driver or cabbie, and sometimes as a
     chauffeur or hackie.
  
     Note: Taxicabs may be engaged by a prior appointment made,
           e.g. by telephone, or they may cruise for passengers,
           i.e. they may drive in city streets and stop to pick up
           pasengers when they are signalled by a prospective
           passenger. The act of signalling a taxicab (usually by
           a wave of the arm) is often called
  
     to hail a cab or
  
     to flag down a cab.
        [PJC]

  taxi
      n 1: a car driven by a person whose job is to take passengers
           where they want to go in exchange for money [syn: cab,
           hack, taxi, taxicab]
      v 1: travel slowly; "The plane taxied down the runway"
      2: ride in a taxicab [syn: taxi, cab]

  41 Moby Thesaurus words for "taxi":
     autobus, become airborne, bicycle, bike, bus, cab, catch a train,
     chartered bus, chauffeur, clear, cycle, diligence, double-decker,
     drive, entrain, fly aloft, go by rail, hack, hackney, hired car,
     jitney, joyride, jump off, leave the ground, mail coach,
     make a train, motor, motor coach, motorbus, motorcycle, omnibus,
     pedal, post coach, ride, rotate, stage, stagecoach, take a joyride,
     take off, taxicab, wheel