When one conjures up an image of a traditional wood floor, it usually is classic solid-wood flooring. Solid-wood flooring features strips (up to 3 inches wide) or planks (greater than 3 inches wide) made exclusively from one wood species. Such strips and planks, each cut from one piece of lumber, feature tongues and grooves (tabs and slots) on their long, vertical sides that allow them to fit together.
Parquet flooring is another solid-wood flooring option. Parquet flooring tiles are made from small pieces of solid wood laid in intricate geometric patterns such as herringbone and basket weave. Older floors may have individually laid pieces, but modern floors are typically laid in 6- to 12-inch tiles.
Most solid-wood flooring is 3/4 of an inch thick and is installed over a plywood subfloor by nailing or stapling down the strips or planks. But recently, some manufacturers have started offering solid-wood flooring products that come in other thicknesses— such as 5/16 of an inch—and are capable of being glued down over a concrete subfloor. Caution is advised when taking this approach, however, because solid-wood strips or planks expand and contract significantly with temperature and humidity changes and are particularly susceptible to the effects of moisture. 
Be sure to check the moisture conditions of your concrete slab before considering this installation method. Also be aware that because of solid-wood flooring’s sensitivity to moisture, it should never be installed in a below–ground level room such as a basement.
Most of today’s wood floors are coated with waterborne urethanes or impregnated acrylics that are durable, highly resistant to water, and require very little care. (For more on finish options, see the article on Wood Flooring Finishes.) Unfinished solid-wood floors are still available, however, for those homeowners who would prefer to sand, stain, and seal their floor themselves. Throughout its lifetime, a solid-wood floor can be sanded several times—down to 1/32 of an inch above the tongue of the strip or plank.
