Hutong and Siheyuan 胡同与四合院

The word "hutong" (hú tóng 胡同) means "water well"(shuǐ jǐng 水井) in Mongolian. The Mongolians keep the nomadic tradition of settling down around springs or wells. A hutong is the passage formed by lines of siheyuan (sì hé yuàn 四合院, four-side enclosed courtyards). Strictly, hutong alleys are less than nine meters wide. Most hutongs in Beijing run in an east-west or north-south direction, with most houses facing south to take in as much sunshine as possible.
Hutong
A standard siheyuan  usually consists of houses on its four sides with a yard in the center. The gates are usually painted red and have large copper door rings. Usually, a whole family lives in compound. The elder generation lives in the main house standing at the north end, the younger generations live in the side houses, and the south house is usually the family sitting room or study.

Hutong joins hutong, and siheyuan meets siheyuan to form a block. Blocks join with blocks to form the whole residential constructions.

胡同和四合院
      过去，北京是由千百万大大小小的四合院背靠背、面对面、平排并列有序地组成的。为出入方便，每排院落间必要留出通道，这就是胡同。

Hutong      胡同，是北京特有的一种古老的城市小巷。在北京，胡同浩繁有几千条，它们围绕在紫禁城周围，大部分形成于中国历史上的元、明、清三个朝代。在这些朝代的鼎盛时期，帝王为了“建皇极而隆上仪”，“袭周官之制度地居民”。北京城以皇宫为中心，街道全部按经纬排列。正规的胡同，集中在皇宫附近的东西两侧，沿街道由南向北整齐的排列，其中民居多为皇亲贵族。简陋的胡同，大多在离皇宫较远的南北两个方向，其中民居多为商贾平民。

Siheyuan      胡同中主要建筑，几乎全部是四合院。这是一种由东西南北四座房屋，以四四方方对称形式围在一起构成的封闭式建筑。根据其中居民社会地位的高低贵贱，它有繁简大小之分。高官富贾的大四合院，建筑考究，庭院廊柱、雕廊画栋，附带前后跨院。平民百姓的小四合院，构筑简单，门面狭窄，房墙低矮。胡同，实质上是许许多多、大大小小、一个紧挨一个地排列起来的四合院之间的通道。

      为便于采光，讲究的四合院都坐北朝南，其排列结果，胡同多数成为东西走向。为了便于沟通，在较大胡同之间又有许多南北走向的小胡同。整座北京城，如同放大的四合院，东西南北基本对称，布局严谨，气势壮观，周围加高墙以矩形圈围，整齐划一。