cork oak, name for an evergreen species of the oak genus (Quercus) of the family Fagaceae (beech family). The cork oak (Q. suber) is native to the Mediterranean region, where most of the world's commercial supply of cork is obtained. It is cultivated elsewhere as an ornamental and has been introduced into warmer regions of the United States because of its economic value. The bark of the tree is stripped off (about every 10 years) and then processed for shipment as commercial cork. There is a cork layer in all trees but it is not as extensive or valuable as in the cork oak. Cork oak is classified in the division Magnoliophyta, class Magnoliopsida, order Fagales, family Fagaceae.

cork, protective, waterproof outer covering of the stems and roots of woody plants. Cork is a specialized secondary tissue produced by the cork cambium of the plant (see meristem, bark). The regularly arranged walls of cork cells are impregnated with a waxy material, called suberin, that is almost impermeable to water or gases. Commercial cork, obtained from the cork oak, is buoyant in water because of the presence of trapped air in the cavities of the waterproof dead cells. It is also resilient, light, chemically inert, and, because of the suction cup action of the cut cells, adhesive. These qualities make cork valuable for bottle stoppers, insulating materials, linoleum, and many household and industrial items.

Cork, Richard Boyle, 1st earl of: see Boyle, Richard, 1st earl of Cork.

Cork, county (1991 pop. 410,369), 2,881 sq mi (7,462 sq km), SW Republic of Ireland. Cork is the county seat. Largest of the Irish counties, it has a rocky and much-indented coastline (Bantry, Dunmanus, Roaringwater, Courtmarsherry, Clonakilty, and Youghal bays, and Kinsale and Cork harbors). The interior has wild rugged mountains rising as high as 2,239 ft (682 m) and fertile valleys (notably of the Bride, the Blackwater, the Lee, and the Bandon). The main occupations are farming (dairying, raising livestock, and growing grains and sugar beets) and fishing. There is a growing manufacturing sector, centered around the city of Cork, which includes products as diverse as tweed cloth and electronic components. There is a large oil refinery at Whitegate. Cóbh is an important transatlantic harbor. Tourism is important, and notable attractions include prehistoric remains (dolmens and stone circles), the ruins of medieval abbeys and churches, and Blarney Castle.

Cork, city (1991 pop. 174,000), county town of Co. Cork, S Republic of Ireland, on the Lee River near its mouth on Cork Harbour. The oldest part of the town rests on an island between the north and south branches of the Lee, which is crossed by numerous bridges. Exports are largely farm produce (dairy products, grain, livestock), cloth, and fish. Imports include coal, raw materials, fertilizers, grain, machinery, and automobile parts. Machinery, chemicals, processed foods, whiskey, and rubber, leather, cotton, and woolen products are manufactured. There are also oil storage depots, a power station, and an international airport. In the 9th cent. the Danes occupied Cork and walled it. Dermot MacCarthy ousted the Danes and in 1172 swore allegiance to Henry II of England. Oliver Cromwell occupied Cork in 1649, and the duke of Marlborough in 1690. Many public buildings were destroyed in the nationalist disturbances of 1920, and the Sinn Féin lord mayor was murdered by the British constabulary. Terence MacSwiney succeeded him and died in jail in London after a hunger strike. Educational institutions include University College (constituent college of the National Univ. of Ireland) and a school of art. The Protestant St. Finbarr's Cathedral, the Roman Catholic cathedral, the Church of St. Ann, and the Carnegie Library are noteworthy.

Boyle, Richard, 1st earl of Cork, 1566-1643, English settler in Ireland. He first went to Ireland in 1588 and in 1602 purchased for a small sum Sir Walter Raleigh's large landholdings in Cork, Waterford, and Tipperary. His energy and success in improving the lands, building mills, establishing ironworks and other industries, founding towns, and creating trade were remarkable and won him rapid advancement. Created earl of Cork in 1620, he was appointed (1629) one of the lord justices of Ireland and in 1631 became lord high treasurer of the kingdom. In this position he came into conflict with Thomas Wentworth (later 1st earl of Strafford), who arrived in Ireland as lord deputy in 1633. In their long struggle Strafford at first was successful in depriving Boyle of a large part of his privileges and income, but Boyle's patient marshaling of the forces of opposition to Strafford's Irish program was an important factor in the latter's downfall. Two of his seven sons became well known—Roger Boyle, 1st earl of Orrery, and Robert Boyle, the scientist.

Outer bark of the evergreen cork oak (Quercus suber), native to the Mediterranean. In its broad sense, cork consists of the irregularly shaped, thin-walled, wax-coated cells that make up the peeling bark of many trees, but commercially only cork-oak bark is called cork. Cork is obtained from the new outer sheath of bark that forms after the original rough outer bark has been removed. This outer sheath can be stripped repeatedly without hurting the tree. Cork is unique because it is made of air-filled, watertight cells that are a remarkably effective insulating medium. The air pockets make cork very light in weight. Though specialized plastics and other artificial substances have replaced cork in some of its former uses, it has retained its traditional importance as a stopper for bottles of wine and other alcoholic beverages.

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Seaport city (pop., 2002 prelim.: 123,338), southwestern Ireland. The seat of County Cork, it is situated on Cork Harbour at the mouth of the River Lee. Founded as a monastery in the 7th century, it was often raided and was eventually settled by the Danes. It passed to Henry II of England in 1172. The city was taken by Parliamentarian forces under Oliver Cromwell (1649) and by the duke of Marlborough (1690). It was heavily damaged in 1920 during the Irish uprising against England. Its industries include leatherworking, brewing, and distilling.

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