What is the meaning of the term "complete node"?

There seems to be some different interpretations of what the term "full node"implies. For example, there seems to be some disagreement about whether a pruned node is still a complete node.

So: What characteristics must be met to label a Bitcoin client as a complete node?

Is this definition of a "complete graph" correct?

Is it correct to say that:

"A complete graph is a graph in which each vertex is connected to all the other vertices in the graph"

That's how I always thought, the official definition is different (I know).