USE…was Alexander’s term to describe how your entire self acts as an integrated whole in any activity. Any specific part occurs as part of the pattern of activity of your entire self (whole body balance, cognitive/ mental aspects, body or physical responses etc..).

For example, say you want to move your arm to reach in front of you to grab something. To do so requires changes in balance and tensions throughout your whole self; all integrated and executed as mental processes by your brain and nervous system; all overlaid with previous learning and experiences of doing it before in environments like the one you’re in; and all to a greater or lesser degree influenced by your current emotional state etc..

In other words, the use of any one part of you occurs within a larger overall pattern of your entire self in action.

Learning to understand (kinaesthetically) how any single action you make is integrated into a larger pattern of how you use your entire self is real shift: From parts thinking, to whole thinking.