The Thai greeting referred to as the wai , The higher the hands are held in relation to the face and the lower the bow, the more respect or reverence the giver of the wai is showing. The wai is traditionally observed upon entering formally a house. After the visit is over, the visitor asks for permission to leave and repeats the salutation made upon entering. The wai is also common as a way to express gratitude or to apologize.
The word often spoken with the wai as a greeting or farewell is sawatdee sometimes romanized as sawasdee). The word sawatdee is usually followed by khap when spoken by a female and by khrap when spoken by a male person
Greeting have 3 types for respect.