A serrated edge is jagged. When a knife is described as having a serrated blade, its edge is lined with small teeth, similar to a saw's. It will cut tomatoes, bread, and meat more effectively than a smooth-edged blade.
The adjective serrated comes from the Latin word serratus, meaning “notched like a saw.” Most often, it is swords and knives that are described as serrated, but some leaves, like those of the Ash and Maple trees, as well as certain flower petals, like carnations and some tulips, also have serrated edges. Great White sharks have serrated teeth so they can more easily rip the flesh of their prey. Yum.