Nibbler
A tool used for cutting sheet metal. A small section of metal is cut away with each stroke.

Niche
1. Small recessed area or hollow in a wall, which is traditionally used for a statue or vase, etc.
2. A specialized market, industry, or profession. n

Nickel
Silver colored metallic element with an atomic symbol of Ni. Used as a metal plating to protect against corrosion.

Niello
A black alloy used as a decorative inlay in metal surfaces. Made from silver, lead, copper, and sulfur.

Night Seal
A temporary sheet covering of synthetic, waterproof material used to cover an opening in a roof until construction is complete.

Nineteen-Inch Selvage
Also referred to as wide selvage asphalt or SIS, this asphalt roofing has a 17 inch granulated surface and 19 inch non-granulated.

Nippers
Wire cutters.

Nipple
A length of pipe with threading on the ends.

Nipple Extractor
A tool used to unscrew sections of pipe.

NLA
Net Leasable Area. Floor space in a building that is actually under lease and able to be rented to tenants. None leasable space would be hallways, building foyers, areas devoted to utilities, elevators, etc.

NNN
see Net Lease.