A graphical representation of a system that is made up of concentric circles. The innermost circle is the core, and all outer layers are dependent on the core. See onion routing. THIS DEFINITION ...

Worshiped by the Egyptians as far back as 3500 B.C., the onion symbolized eternity because of its concentric-circle construction. One large raw onion has only 63 calories, is made up of more than ...

"Carbon onion" is a kind of giant fullerene, named for its concentric multilayer structure similar to the onion. It is widely used in aerospace, energy, biomedicine, environmental remediation and ...