Yaw
1. A yaw rotation is a movement around the yaw axis of a rigid body that changes the direction it is pointing, to the left or right of its direction of motion.
2. The yaw rate or yaw velocity of a car, aircraft, projectile or other rigid body is the angular velocity of this rotation, or rate of change of the heading angle when the aircraft is horizontal. It is commonly measured in degrees per second or radians per second.
Yaw velocity can be measured by measuring the ground velocity at two geometrically separated points on the body, or by a gyroscope, or it can be synthesized from accelerometers and the like. It is the primary measure of how drivers sense a car's turning visually.
It is important in electronic stabilized vehicles. The yaw rate is directly related to the lateral acceleration of the vehicle turning at constant speed around a constant radius, by the relationship tangential speed*yaw velocity = lateral acceleration = tangential speed^2/radius of turn, in appropriate units.
The sign convention can be established by rigorous attention to coordinate systems. In a more general manoeuvre where the radius is varying, and/or the speed is varying, the above relationship no longer holds.
Merriam-Webster's Collegiate® Dictionary, Eleventh Edition https://www.merriam-webster.com/dictionary
YourDictionary https://www.yourdictionary.com/
Omega Company https://www.omega.com/en-us/resources/