Is honeycomb a common noun

Yes, the noun 'honeycomb' is a common noun, a general Word for a structure of hexagons made of wax by bees to store honey or develop young bees; a general Word for a structure resembling these hexagons; a Word for any honeycomb of any kind.

The Word 'honeycomb' is also a verb: honeycomb, honeycombs, honeycombing, honeycombed.