Nitrogen is a chemical element with the symbol N and atomic number 7. It is the lightest pnictogen and the seventh element of the periodic table. Nitrogen is a common element in the universe, estimated at about seventh in total abundance in the Milky Way and the Solar System. At standard conditions, nitrogen is a colorless, odorless, tasteless diatomic gas with the formula N2. It is a constituent of Earth's atmosphere, at 78.08% by volume. Nitrogen is necessary for life and is found in amino acids, proteins, nucleic acids, and chlorophyll.

Nitro is a short for nitroglycerin, a chemical compound with the formula C3H5N3O9. It is a colorless, oily, explosive liquid that is used in dynamite and other explosives. Nitroglycerin is also used in rocket propellants and as a vasodilator medication to treat heart conditions such as angina.

In summary, nitrogen is a chemical element that is essential for life, while nitro is a short for nitroglycerin, an explosive compound.