Liberia UK /laɪˈbɪə̯.ri.ə/US /laɪˈbɪɹ.i.ə/ noun2 •A country in West Africa, on the Atlantic Ocean, with Monrovia as its capital. Official name: Republic of Liberia.Liberia was founded in 1822 by the American Colonization Society whose goal was to resettle freed slaves in Africa. — 2025 •The provincial capital of Guanacaste, Costa Rica.