Thanks Islander2, I agree.
... but when you demo the primary EoC you show them with the aircraft in the reference attitude (approx cruise) and then demo in a climbing turn that the elevator still affects pitch and that the rudder still yaws the aircraft left/right from the pilot's perspective and irrespective of the aircraft's attitude.
HFD, I'm not trying to change any of that, I'm just asking you to recognise that the aircraft
does yaw when it changes heading (except in the extreme case of 90 degrees bank when it's all pitch).
Pick a point on the horizon. Wings level, kick the left rudder. We agree that the point moves left to right across the windscreen, as the aircraft yaws to the left, right? That's how the pilot sees yaw, as a movement left <-> right across the windscreen of that distant point.
Now roll into a balanced level left turn at 15 degrees of bank. Does the point move left to right across the windscreen in the turn? You bet it does. It moves a little bit downwards as well, but it certainly moves left to right, so the aircraft
is yawing. That
is the "flight dynamics definition of yaw".