Plain English Meaning
The kinds of trouble that show up mostly when an instructor and a learner are flying together — things like confusion over who has the controls, the instructor being too busy teaching to notice a problem, or waiting too long to take over. They are the predictable danger zones of the training cockpit.
Full Definition
The recurring categories of hazard that arise specifically during flight instruction, where the presence of two pilots, the training environment, and the instructional task itself create risks that would not exist on a normal flight. These typically include negative transfer of learning, distractions caused by teaching duties, ambiguity over who is flying the aircraft, delayed instructor intervention, and the additional workload of managing both the lesson and the safety of flight.