Quiescence

Quiescence is a reversible nonproliferating cellular state, often designated $G_0$, from which suitable signals can permit re-entry into the cell cycle. A biological cell in quiescence can retain active metabolism, maintain its specialized functions and respond to its environment. This distinguishes quiescence from cell death and from irreversible loss of proliferative capacity. For example, some resting lymphocytes resume cell proliferation after activation. ^[ref]