start up phrasal verb ( see also ↑ start )
1 . if you start up a business, company etc, or it starts up, it begins to exist:
Tax breaks help new companies start up.
start something ↔ up
Jordan started up a band of his own.
2 . if an engine, car etc starts up, or you start it up, it begins working:
The driver got back into the car and started up.
start something ↔ up
Rory started up the engine and got the vehicle moving.
3 . if a sound, activity, or event starts up, it begins to exist or happen:
The crickets had started up now that it was evening.