Meeting ID :
Meeting ID is the meeting number associated with an instant or scheduled meeting. The Meeting ID can be a 9 or 10 digit number. The 9 digit number is used for instant, scheduled or recurring meeting. The 10 digit number is used for Personal Meeting IDs.
UUID:
We use UUID (Universal Unique Identifier) to uniquely identify meetings & users. Since its almost guaranteed to be different from any other meeting or user UUID generated. The length is usually 25 but can be longer at times.
Here is some additional information which can be helpful:
One meeting can be launched many times, there is only one meetingID of one meeting, but it will generate many meeting UUIDs. One meeting instance will have one meeting UUID.
So one meeting can only have one meetingID, but it can also have many meetingUUIDs.
Meeting UUID is used to retrieve the past meeting instance. If the customer use the meetingID to retrieve the past meeting data, it will take the last meeting instance.