The word hutong came from the Mongolian language about 700 years ago. The original Mongolian word was hottog, meaning " water well." In other words, it means a place where people live, because people always gather where there is water. Today in Beijing, the word hutong means a small alleyway or lane. They are typical of the old part of Beijing and are formed by lines of siheyuan (a compound made up of rooms around a courtyard ) in which most Beijing residents used to live.

In old China, there were clear definitions of what was a street and what was a lane. A 36-metre-wide road was called a big street and an 18-metre-wide road was called a small street. A 9-metre-wide lane was called a hutong. Most of the hutongs in Beijing run east-west or north-south. This is because most siheyuan were built along such axes according to the rules of feng shui and to take in more sunshine and resist cold winds from the north. Of course, not all hutongs follow the straight and narrow. There are also slant hutongs, half hutongs and blind hutongs. Beijing's shortest hutong is just 10 metres long and the narrowest is only about 40 centimetres wide. Some hutongs have more than 20 turns. As such, they are often a maze through which it is fascinating to wander, as long as you're not afraid of getting lost.