The term 'DRIVER's Seat' can be broken down into three crossword solutions: HELM (4 letters), MASTERY (7 letters), and UPPERHAND (9 letters). The term 'DRIVER's Seat' is a metaphor for being in control of a situation. The word HELM refers to the steering wheel of a vehicle, which is used to control the direction of the vehicle. MASTERY implies having complete control over something, while UPPERHAND suggests having an advantage or being in a superior position. Together, these words suggest that the person in the DRIVER's Seat is in control and has the advantage.