indeterminate sentence

Definition from Nolo’s Plain-English Law Dictionary

A prison sentence that consists of a range of years (such as "five to ten years"). The state parole board holds hearings that determine when, during that range, the convicted person will be eligible for parole. The principle behind indeterminate sentences is the hope that prison will rehabilitate some prisoners; those who show the most progress will be paroled closer to the minimum term than those who do not. Compare: determinate sentence

Definition provided by Nolo’s Plain-English Law Dictionary.