Thai Nicknames
Just about every Thai person has a nickname by which they are known informally, given to them by their parents at birth. The pervasive use of nicknames in this way apparently comes from the old belief that evil spirits ( ปีศาจ bpee-sàat ) are constantly on the lookout for newborn children to snatch away and control, but using a nickname instead of a normal Thai name confuses the spirits and helps to keep the child safe. This is not a widespread belief nowadays of course, but nonetheless the use of nicknames remains so widespread in Thailand that it's not uncommon for friends to know each other for years and yet not know each other's real name and surname.
The nicknames given may be a contraction of their real name, but most often Thai parents take inspiration for the nickname from a wide variety of other sources instead. Names based on someone's appearance at birth are common. These include: