Ritual and respect
Kru
Also written khru
What it means
Teacher. Used as a title before a trainer name, and the word at the centre of the sport, since the wai kru itself is a bow to the teacher.
Calling a trainer Kru followed by their name is normal, correct and appreciated. It costs nothing and it is noticed.
The relationship implied is closer than coach in the Western sense. A trainer who takes you on is expected to look after you, and you are expected to show up.
Related
Words that go with it
Ajarn
A senior teacher, a step above kru in seniority and usually applied to the person who runs the camp or who taught the trainers.
Wai kru ram muay
The ritual a fighter performs in the ring before a bout, paying respect to their teacher, their camp and the sport. It is danced rather than fought, and it is not decoration.