Basically, there are 2 types of hardwood:

Engineered & Solid

Hardwood and Solid Core.GIF

About 90% of the hardwood sold is Engineered, since it tends to hold up better over time.  Engineered wood has a single layer of the actual wood on top, and then multiple layers (or sheets) of plywood underneath.  This gives it more room to move and breath.  In contrast, Solid Wood a solid piece of wood with no layers.

American Traditions Collection.GIF
Renaissance Collection.GIF
Heritage Collection.GIF