A Gurmata (literally, guru's intention) is an order paon a subject that affects the fundamental principles of Sikh religion and is binding upon all Sikhs. Gurmata is similar to Fatwa in the Muslim tradition with a difference that Fatwa is not binding on all Muslims while Gurmata is binding on all Khalsa, it is not binding on non Khalsa Sikhs.
References
Gurmata Wikipedia(Text) CC BY-SA