Why is the rocket called ignition and not fired?

There is a time difference of about 3 seconds between ignition and launch, which directly means that the launch is inaccurate. The rocket was launched from the ground control center in countdown to zero, and the first stage rocket engine was ordered to ignite. In the earth-shattering roar, the rocket rose slowly from the ground.

The accelerated flight phase has begun. After a few tens of seconds, the launch vehicle began to slowly change in the predetermined direction according to the predetermined procedure. 100 seconds later, at an altitude of about 70 kilometers, the first stage rocket engine was shut down and separated, and the ignition of the second stage rocket continued to accelerate. At this time, the rocket has flown out of the dense atmosphere, and the fairing of the satellite can be thrown away according to the procedure. When the rocket reaches the predetermined speed and altitude, the third-stage rocket engine is shut down and separated, and the accelerated flight segment ends. Subsequently, the launch vehicle uses the obtained energy to start inertial flight under the action of the earth's gravity until it reaches the position tangent to the predetermined orbit. At this time, the third stage rocket engine ignited and began the final accelerated flight. When accelerating to a predetermined speed, the third stage engine is turned off. The carrying mission of the rocket is completed.