v.1. To initiate or begin some conversation or relationship: They often see each other on the bus, but neither of them ever strikes up a conversation. My best friend and I struck it up while working together in the Peace Corps.
2. To reach some agreement: You might be able to get a discount if you strike up a deal with the storekeeper.
3. To start to play or sing something: A few of the musicians struck up a waltz. Everybody got up to dance once the band struck up.
4. To cause something to start to play or sing: Strike up the orchestra and let the celebration begin!