The quality or state of being long, in space or time; extent; duration; as, some sea birds are remarkable for the length of their wings; he was tired by the length of the sermon, and the length of his walk.

the property of being the extent of something from beginning to end; "the editor limited the length of my article to 500 words"

Extent of the course from one end to the other.

One lap; from one end of the pool to the other.

The extent of the competitive course from end to end. See lap.