屋顶(roof)
建筑物顶部覆盖部分。屋顶曾被建造成各种各样的形式－－平的、斜的、拱状的、圆屋顶式，或是这几种样式的结合－－依据地区、技术和美观方面的考量而定。用茅草盖的、往往有所倾斜的屋顶是最早的屋顶样式，至今仍在非洲乡村或其他地方被采用。在历史上，平屋顶多被用在较乾旱的地方，因为在这些地方，屋顶的排水并不重要，如在中东和美国西南部。19世纪出现了防水的新型屋顶材料，使得平屋顶更为普遍，钢筋混凝土的使用也使得平屋顶更加实用。倾斜屋顶有多种不同形式，最简单的一种是倚靠式（或棚式）屋顶，只有一个斜面。有两个斜面的屋顶在两端各成一个三角形，称为山形墙屋顶。带斜脊的屋顶有倾斜的侧面和在斜向突出的拐角处汇合的末端。复斜屋顶在两侧各有两个斜面，上方的斜面不如下方的陡。复斜屋顶在四个面上都各有两个斜面，一个较浅的上部斜面和一个较陡的下部斜面。
English version：
roof
Covering of the top of a building. Roofs have been constructed in a wide variety of forms—flat, pitched, vaulted, domed, or in combinations—as dictated by regional, technical, and aesthetic considerations. Thatched roofs, usually sloping, were the earliest type and are still used in rural Africa and elsewhere. Flat roofs have historically been used in arid climates where drainage of water off the roof is not important, as in the Middle East and the southwestern U.S. They came into more widespread use in the 19th century, when new waterproof roofing materials and the use of structural steel and concrete made them more practical. Sloping roofs come in many different varieties. The simplest is the lean-to (or shed) roof, which has only one slope. A roof with two slopes that form a triangle at each end is called a gable roof. A hipped (or hip) roof has sloping sides and ends meeting at inclined projecting angles called hips. The gambrel roof has two slopes on each of its two sides, the upper being less steep than the lower. The mansard roof has two slopes on all four sides, a shallower upper part and a steeper lower part. See also hammer-beam roof, lamella roof.
