Composite honeycomb is any artificial structure inspired by the shapes honeybees use to build their hives. Our understanding of the structural benefit of isolated cell structures dates back over two thousand years, though its widespread application in engineering and construction only began around the early 20th century.
Honeycomb structures don't necessarily mirror the hexagonal shape of honeybee wax—they also include simple cellular shapes that are more square. The benefit of these materials is mainly that they're lighter, but retain the strength of more dense elements.
This convenient win-win makes them useful for all sorts of applications, from packing material for shipping and logistics, to home construction pieces like doors and walls, to advanced engineering projects like airplanes and helicopters. They're made from a wide range of materials, from cardboard, to plastic, to aluminum, to advanced materials like Nomex, a paper thin variant of Kevlar.