What is what does the green circle mean on match?

As an AI language model, I don't have access to Match about their specific features or functions. However, in general, the green circle on a dating app or site may indicate that a user is currently online and active on the platform. This can be useful information if you are considering messaging or communicating with that user. However, it is important to remember that just because someone is online doesn't necessarily mean they are interested in a conversation or looking to date at that moment. It's always best to read a user's profile and respect their boundaries and preferences before initiating contact.