a period of time between two dates or events
over/within/in a span of something
Over a span of ten years, the company has made great progress.
It'll be difficult to hire that many new staff in such a short time span.
the length of time over which someone's life, ability to pay attention to something etc continues
Captivity vastly reduces the life span of whales.
the part of a bridge, arch etc that goes across from one support to another
the distance from one side of something to the other:
a bird with a large wing span