Usually a meeting means that at least 3 persons meet, talk and, finally, take some decisions about whatever they are interested in. It can take a few minutes or a few days, with results that can vary from unsatisfactory to excelent. Anyway, there are a few basic requirements that ensure that a meeting is successful: purpose (the resons and the objectives for the meeting), leader (the person that keep things on track), process (the way the meeting is done and how you are getting to a concensus), agenda of items to be discussed (and you must stick to them) and the record of the meeting.
One problem is that when a group of people (remember: at least 3 of them) is assembling and they know each other it’s inevitable that social chatter ensues. So, you should always have an agenda to structure the meeting and to cut down on wasted time.