What is the difference between a swath and sling?

A swath is a line or strip of cut crops or grass left on the ground by a mowing machine or scythe. A sling is a device consisting of a piece of material, such as cloth or rope, that is used to throw or hurl objects or to support or lift someone or something.

To summarize, a swath is the result of mowing, while a sling is a tool for throwing or holding.