tower

tower, structure, the greatest dimension of which is its height. Towers have belonged to two general types. The first embodies practical uses such as defense (characteristic of the Middle Ages), to carry bells, beacons, or antennas, and to utilize maximum floor space in a given area, as in modern skyscrapers. The second type is used to symbolize the authority and power of religious and civic bodies, as in the churches and town halls of Europe; skyscrapers also perform a similar function for modern corporations. The earliest use of tall structures for ritual and symbolism is seen in the Babylonian ziggurat. The temple architecture of India had a variety of pyramidal and cylindrical masonry towers. The many-storied pagoda in wood was a part of early Chinese and Japanese temple architecture. The minaret belongs to Islamic religious architecture. Used for defensive purposes in the early Middle Ages in Western Europe, towers with massive masonry walls served as refuges and lookouts. Many 9th- and 10th-century round defense towers remain in Ireland and a few in Scotland, including one at Brechin. Castles had their donjons or keeps, of which the 11th-century Tower of London shows a high development. Of the fortified towers that Italian nobles built even for their city dwellings numerous examples remain, notably at San Gimignano. The earliest existing church towers in Europe were those of the 5th and 6th cent. in Ravenna, Italy. There the bell tower, or campanile, stood detached from the church building itself; another example is the celebrated bell tower at Pisa (1174). In English and French Romanesque churches a high tower rises over the crossing of nave and transepts, and the west end generally possesses lower twin towers. The relatively simple Romanesque towers generally had square or round shafts with many blind arcades in horizontal tiers and were topped by a simple octagonal or conical spire. They developed into the higher, elaborate type of Gothic, decorated with pinnacles and canopied niches. Towers of extreme lightness and intricacy were developed in the late Gothic period, as in the cathedrals at Rouen, Vienna, and Antwerp. With the Renaissance the classical orders were incorporated into tower design. Particular success was attained in the tapering pyramidal compositions of Sir Christopher Wren's numerous London towers, including those of St. Paul's Cathedral. English churches, e.g., St. Martin-in-the-Fields by James Gibbs, set the pattern for the typical New England church with the wooden tower and steeple rising directly over the entrance vestibule. In the 20th cent. towers have often taken the form of skyscrapers. Notable modern towers of varied design and function include the highly original Einstein Tower at Potsdam by Erich Mendelsohn and Frank Lloyd Wright's Johnson tower with glass tubing at Racine, Wis.

---

tower

Any freestanding or attached structure that is relatively tall in proportion to its base. The Romans, Byzantines, and medieval Europeans built defensive towers as part of the fortifications of their city walls (e.g., the Tower of London). Indian temple architecture uses towers of various types (e.g., the sikhara). Towers were an important feature of churches and cathedrals built in the Romanesque and Gothic periods. Some Gothic church towers were designed to carry a spire; others had flat roofs. The Italian campanile could either be attached to a church or freestanding. The use of towers declined somewhat during the Renaissance but reappeared in Baroque architecture. The use of steel frames enabled buildings to reach unprecedented heights; the Eiffel Tower in Paris was the first structure to reveal the true vertical potential of steel construction.

---

tower

(1) A floor-standing cabinet taller than it is wide. Desktop computers can be made into towers by turning them on their side and inserting them into a floor-mounted base.

(2) (Tower) Earlier series of Unix-based single and multiprocessor computer systems from NCR that used the Motorola 68000 family of CPUs.

---

tower

1. a tall, usually square or circular structure, sometimes part of a larger building and usually built for a specific purpose

2. a mobile structure used in medieval warfare to attack a castle, etc.

---

tower [tau̇·ər]

(chemical engineering)

A vertical, cylindrical vessel used in chemical and petroleum processing to increase the degree of separation of liquid mixtures by distillation or extraction. Also known as column.

(electromagnetism)

A tall metal structure used as a transmitting antenna, or used with another such structure to support a transmitting antenna wire.

(engineering)

A concrete, metal, or timber structure that is relatively high for its length and width, and used for various purposes, including the support of electric power transmission lines, radio and television antennas, and rockets and missiles prior to launching.

(mathematics)

For a setSwith a given algebraic structure, this is a set of subsets,S₀=S,S₁,S₂, … ,S_n, such thatS_i+1is a subset ofS_i,i= 1, 2, … ,n- 1, and eachS_iis closed under all possible operations in the algebraic structure ofS.