* Compound: A compound is formed when two or more different elements chemically combine in a fixed ratio. NH3 is made up of nitrogen (N) and hydrogen (H) atoms, making it a compound.

* Molecule: A molecule is formed when two or more atoms bond together. NH3 has one nitrogen atom bonded to three hydrogen atoms, making it a molecule.

Therefore, NH3 (ammonia) is both a compound and a molecule.