What is the term for a turn in which the clock and the turn coordinator are used to change heading a definite number of degrees in a given time?

The term for a turn that specifically utilizes the clock and turn coordinator to change the heading by a definite number of degrees in a given time is referred to as a Timed Turn. This method allows pilots to achieve a precise turn based on time and the aircraft's performance characteristics, ensuring accuracy in navigation and attitude control.

By timing the turn, pilots can ensure that they complete a specific heading change in a planned amount of time, which helps in maintaining situational awareness and improves the effectiveness of flying maneuvers, especially in instrument flying conditions.

While terms like Standard Rate Turn and others exist, they refer to different aspects of turning dynamics rather than the precise timing and heading change specified in the question. Standard Rate Turn, for example, indicates a turn where the aircraft completes a 360-degree rotation in two minutes, but it does not explicitly involve changing heading based on a timed approach.

Thus, Timed Turn is the correct terminology for this specific technique of turning that integrates timing with heading adjustments.