catflap.org Online Dictionary Query

  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]