nanometer [nan o me ter]
A distance of one billionth of a meter.
niacin [nye uh sin]
Part of Vitamin B3; the body requires Niacin in order to convert food into energy and maintain normal functioning of the skin, nerves and digestive system.
nicotine [nick' o teen]
the addictive substance in cigarettes
nitrate [ni trate]
nutrients and inorganic fertilizer that enter the water supply from agricultural, industrial, and waste dump sites
nutrient [new' tree ent]
A substance or part of a substance that provides nourishment or fuel to support life.