1. to maintain a constant speed without accelerating or decelerating
The driver tried to preserve speed on the highway despite traffic conditions.
O motorista tentou manter a velocidade na rodovia apesar das condições do trânsito.
2. in aviation or nautical contexts, to keep aircraft or vessel at a steady velocity
The pilot adjusted the throttle to preserve speed during descent.
O piloto ajustou o acelerador para manter a velocidade durante a descida.