Natural finish- A transparent finish which does not seriously alter the original color or grain of the natural wood. Natural finishes are usually provided by sealers, oils, varnishes, water repellent preservatives, and other similar materials.

NEC (National Electrical Code)- A set of rules governing safe wiring methods. Local codes—which are backed by law—may differ from the NEC in some ways.

Neutral wire- Usually color-coded white, this carries electricity from an outlet back to the service panel. Also see hot wire and ground.

Newel post- The large starting post to which the end of a stair guard railing or balustrade is fastened.

Nonbearing wall- A wall supporting no load other than its own weight.

Nosing- The projecting edge of a molding or drip or the front edge of a stair tread.

Notch- A crosswise groove at the end of a board.

Note- A formal document showing the existence of a debt and stating the terms of repayment.

Nozzle- The part of a heating system that sprays the fuel of fuel-air mixture into the combustion chamber.