A "span" refers to the distance or extent between two points. In various contexts, it can describe physical measurements, such as the span of a bridge or the wingspan of a bird. It can also refer to time, indicating a duration, like the span of a person's life or a project timeline. In mathematics, a span can denote the set of all possible linear combinations of a given set of vectors in a vector space. This concept is crucial in fields like linear algebra and engineering, as it helps in understanding the dimensions and relationships within mathematical structures.