Rotation above this we call it roll about y axis we call it pitch, among z axis we call it yaw this we know, but here comes the question you think of an aircraft or a submarine suppose, the body is oriented this way which is heave this displacement or this displacement according to my definition, this is heave what is pitch, rotation, pitch angle is this angle now that means, aircraft can have a pitch of 90 degree, because sometime it can come straight down, but if I if you say somebody the ship is pitching 90 degree then he laugh at you stream hot pitch.