Force is a physical quantity that is used to describe the interaction between objects or systems. It can cause objects to accelerate, change shape, or deform. Friction is one of the types of forces that can act between two surfaces in contact, opposing their relative motion.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Friction, to a physicist. Explanations are generated by AI and may be inaccurate.