taxicab

1. 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.
   

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.