It's called a cincture
A male monk is called a bhiku. A female nun is called a bhikuni.
I beleive that the most senior monk in any monastery is called the Abbot, regardless of their religion.
A monk's hood is called a cowl.
Nothing if the monk is of a religious order. The belt is a simple rope.
The only one I could find is a cookbook called 'Perl Monks Cookbook.' Of course any Bible used by a monk would be called a 'monk's Bible.'
If you mean, "What is a monk called in the English language?", the answer is indeed "monk". If you mean to ask "What are monks of the Anglican Communion are called?", the answer is the same. They are called monks and mainly follow the rule of Saint Benedict.
Patrick Monk and Joan Monk
tonsure
If by 'head monk' you mean the monk in charge of the monastery, the word you're looking for is probably abbot. The name comes from the Hebrew word abba which means father.
It is an abbacy
A monk
Monastery