setback

/set"bak'/, n.

1. a check to progress; a reverse or defeat: The new law was a setback.

2. Archit. a recession of the upper part of a building from the building line, as to lighten the structure or to permit a desired amount of light and air to reach ground level at the foot of the building.

3. an act or instance of setting back: A nightly setback of your home thermostats can save a great deal of fuel.

4. Also, set-back. a downward temperature adjustment of a thermostat, esp. performed automatically, as by a timer.

[1665-75; n. use of v. phrase set back]

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In architecture, a steplike recession in the profile of a high-rise building.

Usually dictated by building codes to allow sunlight to reach streets and lower floors, the building must take another step back from the street for every specified added height interval. Without building setbacks, many of New York City's streets would be in constant shadow. In the 1920s architects drew attention to their setbacks with decorative devices

mosaics; Chinese, Mayan, or Greek motifs; or geometric blocks

but later architects deemphasized them. The International Style glass-wall skyscraper was typically built without intermittent setbacks, but architects met zoning requirements by creating one huge setback at ground level that created a plaza. The late 20th century saw a return to decorative setbacks.

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