The term 胡同 (hútòng) is a special case. It is a loanword from the Mongolian language, and the characters were chosen primarily to represent the sound of the original word, not for their literal meanings.
The word originates from the Mongolian word “huddug,” which means “(water) well.” In the arid climate of Beijing, wells were essential gathering places for residents. The lanes and alleys that developed around these wells came to be known by this name, which was then transliterated into Chinese as 胡同.