Definition:
Face nailing technically means sending any kind of nail perpendicular into a piece of material, with the nail head exposed.
In practice, face nailing usually refers to finish nails or floor staples forced perpendicular into the face of the last row of floorboards. Because it is impossible to reach the groove of tongue and groove flooring by way of blind nailing, the only option is to face nail that last row.
The heads of face nails can usually be seen. But because this is the outermost area of the floor, and because flooring installers typically do a good job of covering the nail heads, their appearance can usually be mitigated.
Examples:
The floor installers face-nailed the last row of floorboards.
