Honeycomb
Honeycomb comes from bees (of course). When using shears on a nest, you get honeycomb.
Honeycomb Block
Honeycomb blocks are made up of four honeycombs in a crafting table.
Honey Block
Honey blocks can be slid down, slowing your descent.
Nests
Bee nests are where the bees make honey for later collection and are where bees go during the night.