تعریف و معنای "[have] {sb} (in the palm|eating out) of {one's} hand"

What is the origin of the idiom "have someone in the palm of one's hand" and when to use it?

The origin of the idiom "have someone in the palm of one's hand" is not precisely known. However, it is thought to have its roots in the ancient practice of palmistry or chiromancy, which involves interpreting the lines and features of a person's palm to gain insight into their character or future. The palm of the hand has long been associated with control, as it is the part of the body used to grasp and manipulate objects. The phrase may have emerged from this association with power and control. It is often used in discussions about power dynamics, manipulation, or personal relationships.