Taxi time is the total time of an aircrafts movement on the ground. Taxi time can be the time it takes an aircraft to go from a hanger or terminal to the runway until cleared for takeoff or the aircraft going from exiting the runway back to the hanger or terminal. It is used by pilots to determine various kinds of information pertinent to the flight such as fuel burn, total fuel loss, weight, take off weight, landing weight, and true airspeed. Since weight planes a huge part in whether an aircraft can takeoff or land the amount of time a plane spends burning fuel on the ground taxiing can greatly alter the planes takeoff or landing distances.
Taxi time also plays a role for the companies owning the planes. No body likes to spend the majority of their flight stuck in the airplane on the ground waiting to take off. So companies try to minimize their taxi time as much as possible as both a convenience to the customer and themselves by minimizing the amount of time the passenger spends in the plane but also saving cost due to the less fuel burn. Charter jets usually have shorter taxi times. The planes need less force to move due to the lighter weight and have lower takeoff speeds allowing them to be off the ground faster. The super mid-sized jet and very light jet are perfect fits both larger and short aircraft.
Air-traffic control also has an investment in taxi time. The shorter an aircrafts taxi time is the faster air-traffic control can get planes in and out of the airport. It is in both the best interest of the pilots and the controlling agency to expedite traffic in and out of the airport as fast as possible and they do this by having efficient taxiways and shorter taxi times. In larger airports there tend to be more runways allowing for the takeoff of many aircrafts at one time.