Plain English Meaning
Pitch and power work together. When you change one, you usually have to change the other to keep the aircraft doing what you want — holding altitude, climbing, descending, or maintaining a target speed.
Full Definition
The interdependent relationship between the aircraft's pitch attitude (nose up or down) and engine power setting, where a change to one almost always requires a change to the other to maintain a desired flight condition such as airspeed, altitude, or rate of climb or descent.
Context Anchor
Seen in instrument flying when a pilot sets a known nose to get a predictable result, such as , a , or a descent.