ground state

noun Physics.

1. the state of least energy of a particle, as an atom, or of a system of particles.

noun

1. the lowest energy state of an atom, molecule, particle, etcCompare excited (def. 4)

n.

1. The state of least possible energy in a physical system, as of atoms or molecules.

1. The state of a physical system having the lowest possible potential energy. For example, an electron in the lowest energy orbital in a hydrogen atom is in a ground state. The ground state of a physical system tends to be stable unless energy is applied to it from the outside; states that are not the ground state have a tendency to revert to the ground state, giving off energy in the process. Compare excited state.