Which scientific term best matches this description: Two or more atoms bound together, either by sharing electrons (covalent bond) or by the electrostatic attraction between oppositely charged ions (ionic bond)?

A) Isotope

B) atom

C) atomic nucleus

D) molecule

Answer: D

Explanation: Two or more atoms bound together, either by sharing electrons (covalent bond) or by the electrostatic attraction between oppositely charged ions (ionic bond). For example, water (H_{2}O) has two hydrogen atoms bound to one oxygen atom.