A heel is the bottom, back part of a shoe or boot that provides elevation. The styling and construction of a heel may vary (i.e., stacked, stilletto, spiked, sculptured, kitten).
About Lug Sole Boots:
Lug Sole Boots are any styling of boot that has a heavy, rubber (or other synthetic) outsole. Lug Sole Boots will typically feature a rugged tread on the outsole.