The Last Chain Gang | Hardest Prison - Geographic History. "Prisoner" is a legal term for a person who is imprisoned. In section 1 of the Prison Security Act 1992, the word "prisoner" means any person for the time being in a prison as a result of any requirement imposed by a court or otherwise that he be detained in legal custody. "Prisoner" was a legal term for a person prosecuted for felony. It was not applicable to a person prosecuted for misdemeanour. The abolition of the distinction between felony and misdemeanour by section 1 of the Criminal Law Act 1967 has rendered this distinction obsolete. Glanville Williams described as "invidious" the practice of using the term "prisoner" in reference to a person who had not been convicted. Read More: en.wikipedia.org/wiki/Prisoner