Étude

An étude (/ ˈeɪtjuːd/; French pronunciation: ​[eˈtyd], a French word meaning study) is an instrumental musical composition, usually short, of considerable difficulty, and designed to provide practice material for perfecting a particular musical skill. The tradition of writing études emerged in the early 19th century with the rapidly growing popularity of the piano. Of the vast number of études from that era some are still used as teaching material (particularly pieces by Carl Czerny and Muzio Clementi), and a few, by major composers such as Frédéric Chopin, Franz Liszt and Claude Debussy, achieved a place in today's concert repertory. Études written in the 20th century include those related to traditional ones (György Ligeti), those that require wholly unorthodox technique (John Cage), and ones that are unusually easy to play.

19th century

Studies, lessons and other didactic instrumental pieces composed before the 19th century are very varied, without any established genres. The pieces in lute instruction books, such as the celebrated Varietie of Lute-Lessons (1610), may be arranged in order of increasing difficulty, but will usually include both simple teaching pieces and masterworks by renowned composers. Domenico Scarlatti's 30 Essercizi per gravicembalo ("30 Exercises for harpsichord", 1738) do not differ in scope from his other keyboard works, and Johann Sebastian Bach's four volumes of Clavier-Übung ("keyboard practice") contain everything from simple organ duets to the extensive and difficult Goldberg Variations.

House

A house is a building that functions as a home, ranging from simple dwellings such as rudimentary huts of nomadic tribes and the improvised shacks in shantytowns to complex, fixed structures of wood, brick, marble or other materials containing plumbing, ventilation and electrical systems. Most conventional modern houses in Western cultures will contain a bedroom, bathroom, kitchen or cooking area, and a living room. In traditional agriculture-oriented societies, domestic animals such as chickens or larger livestock (like cattle) may share part of the house with humans. The social unit that lives in a house is known as a household. Most commonly, a household is a family unit of some kind, although households may also be other social groups or individuals. The design and structure of the house is also subject to change as a consequence of globalization, urbanization and other social, economic, demographic, and technological reasons. Various other cultural factors also influence the building style and patterns of domestic space.