A dispatcher is someone whose work involves receiving messages and organizing the movement of ambulances and other vehicles. Being a dispatcher requires excellent communication skills in a high-pressure environment.
An emergency dispatcher's work day might include getting phone calls from people who need medical assistance or the help of firefighters. A taxi dispatcher, on the other hand, communicates with each cab driver about where to pick up passengers who've called for rides. To dispatch is to send something off quickly, and for most dispatchers, their job is dispatching vehicles.