graphical user interface (GUI) Computer display format that allows the user to select commands, call up files, start programs, and do other routine tasks by using a mouse to point to pictorial symbols (icons) or lists of menu choices on the screen as opposed to having to type in text commands. The first GUI to be used in a personal computer appeared in Apple Computer’s Lisa, introduced in 1983; its GUI became the basis of Apple’s extremely successful Macintosh (1984). The Macintosh’s GUI style was widely adapted by other manufacturers of personal computers and PC software. In 1985 Microsoft Corp. introduced Windows, a GUI (which later grew into an operating system) that gave MS-DOS-based
Ulysses S. Grant.
LIBRARY OF CONGRESS, WASHINGTON, D.C.
Grape (Vitis).
GRANT HEILMAN PHOTOGRAPHY
Grapefruit (Citrus paradisi).
GRANT HEILMAN
© 2006 Encyclopaedia Britannica, Inc.
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computers many of the same capabilities as the Macintosh. In addition to being used for operating-system interfaces, GUIs are used in other types of software, including browsers and application programs.
graphite or plumbago \ I pbm-'ba-go\ or black lead Mineral allo- trope of carbon. It is dark gray to black, opaque, and very soft. Its lay¬ ered structure, with rings of six atoms arranged in widely spaced parallel sheets, gives it its slippery quality. It occurs in nature and is used (mixed with clay) as the “lead” in pencils. It is also used in lubricants, crucibles, polishes, arc lamps, batteries, brushes for electric motors, and nuclear reactor cores.
graptolite Vgrap-to-.lItX Any member of an extinct group of small, aquatic colonial invertebrates that first became apparent during the Cam¬ brian Period and persisted into the Early Carboniferous Period (354-323 million years ago). Graptolites were floating animals that had tentacles and a hard outer covering. They most often have been preserved as impressions on black shales. Graptolite fossils show a gradual develop¬ ment through time, and evolutionary relationships between different grap¬ tolite groups have been discovered and analyzed.
grass Any of many low, green, nonwoody plants that make up the fami¬ lies Poaceae (or Gramineae), Cyperaceae (sedges), and Juncaceae (RUSHes). Only the approximately 8,000-10,000 species in the family Poaceae are true grasses. They are the most economically important of all flowering plants because of their nutritious grains and soil-forming function, and they are the most widespread and most numerous of plants. The cereal grasses include wheat, com, rice, rye, oats, barley, and millet. Grasses provide for¬ age for grazing animals, shelter for wildlife, and construction materials, furniture, utensils, and food for humans. Some species are grown as garden ornamentals, cultivated as turf for lawns and recreational areas, or used as cover plants for erosion control. Most have hollow, segmented, round stems, bladelike leaves, and extensively branching fibrous root systems.
Grass \'gras\, Gunter (Wilhelm) (b. Oct. 16, 1927, Danzig) German novelist, poet, and playwright. Grass was involved in the Hitler Youth, was drafted at age 16 and wounded in battle, and became a prisoner of war. His extraordinary first novel,
The Tin Drum (1959), brought him international fame, and he became the literary spokesman for the Ger¬ man generation that grew up in the Nazi era. Together with Cat and Mouse (1961) and Dog Years (1963), it forms a trilogy set in Danzig (now Gdansk, Pol.). His other works, all politically topical, include The Flounder (1977); The Call of the Toad (1992), about the uneasy rela¬ tionship between Poland and reuni¬ fied Germany; A Broad Field (1995), controversial for expressing his view that reunification was a mistake; and My Century (1999). He received the Nobel Prize for Literature in 1999.
grasshopper Any of the leaping insects of the family Acrididae (short¬ horned grasshoppers) or Tettigoni- idae (long-horned grasshoppers), both in the order Orthoptera. Grass¬ hoppers are most common in tropical forests, semiarid regions, and grass¬ lands. Colours range from green to olive or brown, sometimes with yel¬ low or red markings. Grasshoppers eat plant material and may damage crops. Some species are more than 4 in. (11 cm) long. The male can pro¬ duce a buzzing sound either by rub¬ bing its front wings together or by rubbing toothlike ridges on the hind legs against a raised vein on each front wing. Grasshoppers are a favourite food of many birds, frogs, and snakes. See also katydid; locust.
Grateful Dead U.S. rock group. It was formed in San Francisco in the mid-1960s by Jerry Garcia (1942-95) on guitar, Phil Lesh (b. 1940) on bass, Ron (“Pigpen”) McKernan (1945-73) on keyboards, Bob Weir (b.
1947) on guitar, and Bill Kreutzmann (b. 1946) on drums. The Grateful Dead emerged from the Haight-Ashbury psychedelic-drug-and-music scene, later gaining fame for performing at the Monterey Pop Festival (1967) and Woodstock. Though they regularly released albums, their focus was on live music. They became one of the country’s most suc¬ cessful touring bands, known for Garcia’s marathon four-hour musical meanderings and for their entourage of “Deadheads,” a devoted legion of nomadic fans who followed the band in spirited makeshift communities. In the late 1980s a new generation of fans made the Grateful Dead the most successful touring band in the world. They stopped touring after Garcia died of a heart attack at a drug rehabilitation centre.
Gratian Vgra-shonV Latin in full Flavius Gratianus Augustus (b.
359, Sirmium, Pannonia—d. Aug. 25, 383, Lugdunum, Lugdunensis) Roman emperor (r. 367-83). He originally shared the office with his father, Valentinian I (r. 364-75), and his uncle, Valens (r. 364-78). He later shared authority with his 4-year-old half brother, who was supported by the army. Following his uncle’s death at the disastrous Battle of Adrian- ople, he became ruler of the Eastern Empire and summoned Theodosius I to share power with him. Influenced by St. Ambrose, Gratian omitted the words pontifex maximus (“supreme priest”) from his title. He was mur¬ dered opposing the usurper Magnus Maximus.
Grattan \'gra-t 3 n\, Henry (b. July 3, 1746, Dublin, Ire.—d. June 6, 1820, London, Eng.) Irish politician. He entered the Irish Parliament in 1775 and, as a brilliant orator, soon became the leading spokesperson of the Irish nationalist agitation. His movement gained momentum; he forced the British in 1779 to remove restraints on Irish trade and in 1782 to relin¬ quish their right to legislate for Ireland. In 1800 he headed the unsuc¬ cessful opposition to the union of England and Ireland. In 1805 he was elected to the English House of Commons, where he fought for Catholic emancipation for his last 15 years.
gravel Aggregate of more or less rounded rock fragments coarser than sand (i.e., more than 0.08 in., or 2 mm, in diameter). Gravel beds in some places contain heavy metallic ore minerals, such as cassiterite (a major source of tin), or native metals, such as gold, in nuggets or flakes. Depos¬ its accumulate in parts of stream channels or on beaches where the water moves too rapidly to permit sand to remain. Because of changing condi¬ tions, gravel formations generally are more limited and more variable in coarseness, thickness, and configuration than sand or clay deposits. In many regions gravel terraces (or raised beaches) extend great distances inland, indicating that the sea at one time stood higher than it does today. Gravels are widely used building materials.
Graves, Michael (b. July 9, 1934, Indianapolis, Ind., U.S.) U.S. archi¬ tect and designer. He studied at Harvard University and in 1962 began a long teaching career at Princeton University while designing private houses in the abstract and austere style of orthodox Modernism. In the late 1970s he rejected Modernist expression and began seeking a larger, postmodernist vocabulary. The hulking masses of the Portland Building in Portland, Ore. (1980), and the Humana Building in Louisville, Ky. (1982), display his highly personal. Cubist rendering of such Classical elements as colonnades and loggias. Though considered somewhat awk¬ ward, these and his later buildings (e.g., Indianapolis Art Center, 1996) have been acclaimed for their ironic interpretation of traditional forms. Among his later projects were the restoration of the Washington Monu¬ ment (2000) and the creation of a line of household items, including kitchenware and furniture, for the discount retailer Target.