1. To begin or set in motion; SYN. go, get going.
2. To begin work or acting in a certain capacity, office or job; SYN. take up.
3. To get going or set in motion; SYN. start up.
4. To get off the ground; SYN. start up, begin, embark on, commence.
5. To play in the starting line-up, in team sports.