Board Width.
The width of the individual wood boards make up the floor.  Narrow boards, called Strips, are less than 3 inches wide.  Boards which are three inches or wider are called Planks. The width of individual boards has a dramatic influence on the installed look of the floor. Wide widths can complement a large room, but overwhelm a small area.   Strip and Plank can also be mixed to create a unique, custom look.

Strip	Plank	Strip and Plank

Edge Detail.
Edge or End Detail is the special milling on the edges of each individual board to create visual effects. If you are looking for a dramatic effect, select a beveled edge/end detail that emphasizes the definition of individual boards. Square edges/ends create a smooth and seamless appearance and give a prefinished floor the look commonly found in traditional site-finished floors.

Square	Microbeveled	Eased	Beveled

Engineered Hardwood.
Engineered wood is constructed of mulitple layers of cross grain wood that are bonded together.  It is designed for installation at any house level, including below grade, and it can be installed directly over concrete. Engineered wood with a top layer thinner than 1/10" cannot be refinished; however, it can be recoated to renew the surface of the floor.

Solid Hardwood.
Solid Wood is milled from one piece of wood into boards that are three-quarters of an inch thick.   It should not be installed below grade, as moisture makes it expand and contract.  All solid hardwood can be sanded and refinished if needed (required every 15-20 years).  All urethane coated floors can be recoated as needed to renew the surface of the floor. This is more economical than sanding and refinishing.

The Janka Test.
The hardness of wood flooring is measured by something call the Janka Test.  A .444 inch steel ball is driven into the wood in question to half of the ball's diameter.  Kids and dogs make the Janka Test essential. Wood floor does get scratched and dented through normal use. On top of that, if you have kids or pets, you will have increased concerns about dents and scratches.

While it may make sense to pick the very hardest wood, you should keep a few points in mind.   Soft wood can be hardened to some degree by the application of polyurethene finishes.  Hardwood is nearly always more expensive than the softer and medium-grade woods as it is more difficult to saw, drill and nail than other woods. 

Wood Species  .
Species influences appearance. Traditional oak has pronounced variations in grain and shade, while maple's grain is cleaner and more understated. Today, there are many exotic species available, such as lapacho, tigerwood, and Brazilian cherry, that have a distinctive combination of origin, color and surface characteristics.

Different species have different hardnesses that affect durability. If your floor is likely to take a lot of abuse, consider oak, maple, ash or Brazilian cherry for extra resistance to indentation.