Yaw is the object turning as if it is spinning on a lazy suzan (one of those spinning plate things you get in chinese restaurants), pitch is pointing the nose up or down, and roll is as if the object is doing a barrel roll.
My question is, do these directly relate to the x, y and z axes? as in, is yaw x, pitch y and roll z? Because If I orient a 3D plane forward using the direct x coordinate system (where z is forward, x is right and y is up) yaw pitch and roll would correspond to the y, x and z axes respectively.
Are they always defined by the axes or are they coordinate system specific?