Compound

A compound is a molecule which is composed of more than one element.

Chemical compounds can be fairly simple, such as water (H₂O), which is just one oxygen atom and two hydrogen atoms. Many are moderately complex, like sugars, which consist of no more than a few dozen carbon, oxygen, and hydrogen atoms, e.g. C₆H₁₂O₆. Some are relatively huge (still not visible to the naked eye), such as DNA, which can contain millions of atoms in one double helix crystal.

In general, compounds containing carbon are referred to as "organic compounds".