One of the limits on a chart in which the number of protons in a nucleus is plotted against the number of neutrons that indicate where nuclei can exist. There are two driplines: the proton dripline and the neutron dripline. The proton dripline indicates the maximum number of protons a nucleus can have, with the neutron dripline indicating the maximum number of neutrons a nucleus can have. Dripline nuclei are nuclei that are close to these limits. The position of the proton dripline is better known for most elements than the position of the neutron dripline.