- (intransitive) To rise suddenly.
- He started up when he heard the scream.
- (transitive, intransitive) To begin to operate.
- The four of them started up a law practice.
- The engine started up right away.
- (intransitive, colloquial) To begin.
- They started up playing.
- For quotations of use of this term, see Citations:start up.
to appear suddenly