There are multiple ways to execute this gesture, depending on one’s social class, gender and age. Generally, the higher the hands are in relation to the face and the lower the head is bowed, the more respect the wai-giver is showing.

The 'wai' began as an ancient greeting with which people showed each other they were carrying no weapons. It is also said to be related to a Buddhist religious custom. After certain prayers, it is customary to clasp one’s hands together and bring them down towards the ground three times.

Specifically:

• a younger person (male or female) greets an older person first. You raise both hands, palms close together, and bow your head a little to meet your hands at about the level of your nose.
• When entering a room with numerous older people in it, it is customary for the young person to wai everyone individually.
• The older person accepts the greeting by means of the wai to return the honour.
• Normally Thai people greet each other always and anywhere by means of the wai gesture, but for close friends a wai is not considered necessary.
• In the workplace it is good for junior people to show respect to senior people by means of the wai. Here, hierarchy overrides age; so a person who is older, but less high in the organisation, will wai a person who may be younger, but is higher in rank.

A wai is a way to show respect, but also to say sorry, thank you or forgive me. When a young person has made a mistake or offended an adult, he will quickly raise his or her hands in a wai. This is a common rule in family life too.

When meeting a monk, a lay person will always greet him with a wai. The monk responds to this by saying something to greet the person, but a monk never wais ordinary people. However, amongst themselves, junior monks do have to wai senior monks.

If in doubt, just nod and smile!