start up

verb5

1. •
   To commence the operation of; to activate; to launch.

   • The four of them started up a law practice.
2. •
   To begin to operate.

   • The engine started up right away.
3. •
   To begin.

   • The band started up playing.
4. •
   To begin to make a sound

   • First a solitary blackbird started up, but soon the whole forest was alive with birdsong.
5. •
   To rise suddenly.

   • He started up when he heard the scream.