A is a quantity that must always be stated with magnitude and direction. (Fill in the blank with one word.)

The word that fills in the blank is "vector."

A vector is a mathematical and physical quantity that is defined by both its magnitude and direction. In contrast to scalar quantities, which are described solely by their magnitude (such as temperature or mass), vectors provide more comprehensive information about physical phenomena. For example, velocity, force, and acceleration are all vector quantities. The vector nature of these quantities is essential in fields such as physics and engineering, where understanding both the size and direction of forces or movements is crucial for accurate analysis and predictions. This characteristic distinguishes vectors from scalars, making them an integral part of vector algebra and calculus.