This is what seems to make sense in this specific context.

Mike :)

Each coordinate for this point is associated with a "value" on some basis (e.g., on an axis or, in the case of polar coordinates, a distance and an angle). So one hopes that by dragging the point around with the mouse, the corresponding coordinates in the program move to the relevant place.

I will point out that "Dynamic Geometry" is a registered trademark of Key Curriculum Press, so I recommend you visit the URL below and/or ask your client to obtain their English-language material so you can be consistent.