It sounds like it was a sponsorship of a specific event such as your carnival. "Sponsorship" can mean anything - they support you in some way, help promote, give cash, give in-kind donations. It means what you define it to mean.

Hi
I'm relatively new to the pto scene, last year i was treasurer and I heard from a member that the bank we used was also our sponsor, when i talked to the bank manager he knew nothing of this. They did donate some of their radio ads to promote our carnival though. Is it possible to have a bank or business sponsor and if so what does this usually entail.
Thanks