Some of the standards developed by NWFA include a formal definition of wood, which consists of a working group of wood flooring professionals throughout the supply chain. The team's formal definition of wood flooring is as follows: wood is a kind of hard fiber material, which is formed by the main material of trunk or branch, and under the bark. Wood floor refers to the floor products with solid wood as the top layer and the most wear-resistant surface. Wood flooring can be divided into three categories:
The solid wood floor is a solid wood floor from top to bottom.
The engineering wood floor is solid wood floor from top to bottom. It is usually glued together by multiple wood veneers or slats in the opposite direction.
Composite engineered wood flooring contains solid wood only on wear-resistant surfaces. Liners and cores can be made of any type of composite material.