Process, meetings, teams, and relationships are all communication structures.
A meeting adds agendas, roles, and time boxes to the activity of communication. Process (in a knowledge work context) generally exists to ferry information between actors in a system—not necessarily human actors. A team is a series of people, relationships, and processes organized so work can concrete out of its communication activities. A business relationship is generally to help move information from one area or hierarchical level of the business to another.