1. To maintain a constant or steady speed without acceleration or deceleration
The car can sustain speed of 120 km/h on the highway.
O carro consegue manter uma velocidade de 120 km/h na rodovia.
2. To keep a particular pace or velocity over a period of time
The runner tried to sustain speed throughout the race.
O corredor tentou manter a velocidade durante toda a corrida.
3. In aviation, to continue flying at a particular airspeed
The pilot needs to sustain speed to avoid stalling.
O piloto precisa manter a velocidade para evitar uma parada.