What is a vod aggregator?

Excuse me, could you kindly elaborate on what a vod aggregator actually is? I've heard of the term in the context of digital media and streaming services, but I'm still a bit hazy on the specifics. Is it a platform that brings together various video-on-demand content from different providers, allowing users to access them all in one place? Or does it have a more complex function than that? I'd appreciate any clarification you could offer.