Ulster (Irish: Ulaih, IPA: [ˈkwɪɟɪ ˈʌlˠu / ˈʌlˠi], Ulster Scots: Ulstèr) is one of the four provinces of Ireland, in addition to Connacht, Munster and Leinster. The term is often used informally — and incorrectly — as a synonym for Northern Ireland, one of the constituent nations of the United Kingdom. In fact, three of the nine Ulster counties are part of the Republic of Ireland with the remaining six constituting Northern Ireland.