The force that holds the nucleons (protons and neutrons) together in the nucleus of the atom is the
strong nuclear force.
Explanation:
The strong nuclear force is one of the four fundamental forces of nature and is the strongest of them. It acts between the nucleons (protons and neutrons) and binds them together to form the nucleus. The strong nuclear force is attractive at short distances (about \( 10^{-15} \, \text{m} \)), and it is much stronger than the electrostatic force that tends to push the positively charged protons apart.
Thus, the answer is:
\[
\boxed{\text{Strong Nuclear Force}}
\]