Definitions

1. noun

the act of a vehicle, especially a spacecraft, rising into the air or leaving the ground, typically with the aid of a rocket engine

“The liftoff of the spacecraft marked the beginning of its journey to Mars.”

2. verb

to rise or leave the ground, especially with a loud noise, as a result of a sudden release of energy or a violent explosion

“The fireworks liftoff in the sky, creating a colorful display.”