* Molecule: A molecule is formed when two or more atoms bond together. H2O consists of two hydrogen atoms bonded to one oxygen atom, making it a molecule.

* Compound: A compound is a substance formed when two or more different elements are chemically bonded together. Since H2O contains both hydrogen and oxygen, it is also a compound.

In simpler terms:

* Molecule: Two or more atoms joined together.

* Compound: Two or more different types of atoms joined together.

Since H2O has both multiple atoms and different elements, it fits both definitions.