Soi

In Thailand, a soi (Thai: ซอย [sɔ̄ːj]) is a side street that branches off of a major street (thanon, Thai: ถนน).

[1] An alley is called a trok (Thai: ตรอก).

When walking on the major street towards increasing soi numbers, all the even-numbered sois are on the right side and the odd-numbered ones on the left side of the street.

On lower Sukhumvit road in Bangkok, for instance, the sois are named after important landowners or families of landowners who had land in the area in the past.

A formal address might read "150/1 Soi Sukhumvit 7", referring to the house with the first number after 150 in the seventh soi of Sukhumvit Road.