Metamaterials

A metamaterial (or meta material) is a material which gains its properties from its structure rather than directly from its composition. To distinguish metamaterials from other composite materials, the metamaterial label is usually used for a material which has unusual properties.

The term was coined in 1999 by Rodger M. Walser of the University of Texas at Austin. He defined metamaterials as: "Macroscopic composites having a manmade, three-dimensional, periodic cellular architecture designed to produce an optimized combination, not available in nature, of two or more responses to specific excitation".

Source:
Wikipedia. Metamaterial