What is a Honeycomb ?

A honeycomb is a mass of hexagonal wax cells built byhoney bees in their nests to contain their larvae and stores of honey and pollen.

Beekeepers may remove the entire honeycomb to harvesthoney. Honey bees consume about 8.4 pounds of honey to secrete one pound of wax, so it makes economic sense to return the wax to the hive after harvesting the honey, commonly called "pulling honey" or "robbing the bees" by beekeepers.

The structure of the comb may be left basically intact when honey is extracted from it by uncapping and spinning in a centrifugal machine—thehoney extractor. Fresh, new comb is sometimes sold and used intact as comb honey, especially if the honey is being spread on bread rather than used in cooking or to sweeten tea.

Broodcomb becomes dark over time, because of the cocoons embedded in the cells and the tracking of many feet, called travel stain by beekeepers when seen on frames of comb honey. Honeycomb in the "supers" that are not allowed to be used for brood (e.g. by the placement of aqueen excluder) stays light coloured.

Numerous wasps, especially polistinae and vespinae, construct hexagonal prism packed combs made of paper instead of wax; and in some species (like Brachygastra mellifica), honey is stored in the nest, thus technically forming a paper honeycomb. However, the term "honeycomb" is not often used for such structures.

Sources
http://en.wikipedia.org/wiki/Honeycomb