(1.)The Jizyah is a tax payed by non-Muslims living in Islamic lands (a Thimmi) to the state. Through this tax they are exempt from the duties of Islam like military service and zakat and are protected by the state as well.
(2.)Jizyah was applied to every free male member of the People of the Book, non-Muslim communities living in lands under Muslim rule. The collection of the tax was often the duty of the elders of those community, mainly Bishops or Priests.
Source 1 Islamic Dictionary
Source 2 WordIQ