What best describes a vector quantity?

A vector quantity is best described as a quantity that possesses both magnitude and direction. This means that not only does the vector have a size (magnitude), but it also points in a specific direction, which is crucial in various fields such as physics, engineering, and surveying.

For example, velocity is a vector quantity; it not only tells us how fast an object is moving (magnitude) but also in which direction it is traveling. This duality is critical for accurately describing movements and forces in a three-dimensional space.

In contrast, other descriptions such as magnitude only refer to scalar quantities, which do not have a directional aspect. Quantities like temperature are inherently scalar, as they only convey how much temperature there is without any directional information. Thus, the essence of a vector quantity is its requirement to have both these characteristics, distinguishing it from scalar quantities.