What does frat mean in Latin?

Answer 1

In classical Latin frater means "brother" or sometimes "cousin", which was often a term of endearment for close friends as well as literal brothers.

In Ecclesiastical Latin, frater was the term used for monks, who regarded each other as brothers in Christ. This term became frere in Old French, which mutated into friarin Middle English - this was only applied to the mendicant Orders of friars, to distinguish them from the Orders of monks.

In a monastery, the communal refectory for monks is sometimes confusingly referred to as the "frater". Here the monks would eat in complete silence, while one of the brothers read from a religious text. Sign language developed in monasteries in order for brothers to communicate during such periods of silence.

Answer 2

fraternity