"Metacognition can be considered a synonym for reflection in applied learning theory.
However, metacognition is a very complex phenomenon. It refers to the cognitive control and monitoring of all sorts of cognitive processes like perception, action, memory, reasoning or emoting. It is also plausible that control over such cognitive processes can be either exiplit (people are aware of it, i.e. they have "epistemic feelings" or infer things) or implicit (they don't reflect)."
Via Howard Rheingold