Ci·u·dad Bo·lí·var (sē'ŏŏ-däd' bō-lē'vär, syōō-) A city of east-central Venezuela on the Orinoco River southeast of Caracas. It was founded in 1764 on the narrows (or angosturas) of the river and was popularly known as Angostura. Population: 287,000.