Cork. A species of oak, growing in the south of Europe, especially in Spain and Portugal and in the north of Africa, having a thick, rough bark, for the sake of which the cork tree is often planted. It grows to the height of forty feet, and yields bark regularly every eight years for 150 years. This outer bark, which grows to a thickness of two inches, is the common cork of commerce, and is used for many purposes, especially for stoppers for bottles, inner soles of shoes, etc.