User Datagram ProtocolAn agreed way of doing something. Like a convention, except that protocols tend to be related to processes.. A “best effort” (i.e., no guarantees) way to get a message from one place to another. Used on Layer 4 of the stackRelated to communications: A way of organizing parts of a complicated process (like communications) so that any task relies on tasks below it and feeds the tasks above it. Related to computing: A place in memory where you store “where was I?” information when you go from, say, one function into another. Before starting a new function, you store where you were in the old one so that, when the new function ends and you’re back in the old one, you can figure out where you were and continue on..