Wikipedia
Gurmat (gur-mat, mat, Sanskrit mati, i.e. counsel or tenets of the Guru, more specifically focusing the mind towards the Guru is a term which may in its essential sense be taken to be synonymous with Sikhism itself. Etymologically, Gur means wisdom and Mat means Tenet/Belief. Generally, Gurmat is theology includes teachings of Sikh Bhagats and Sikh Gurus which is incorporated in Guru Granth Sahib.
It covers doctrinal, prescriptive and directional aspects of Sikh faith and praxis. Besides the basic theological structure, doctrine and tenets derived from the teachings of Guru Nanak and his nine successors, it refers to the whole Sikh way of life both in its individual and social expressions evolved over the centuries. Guidance received by Sikhs in their day-to-day affairs from institutions established by the Gurus and by the community nurtured upon their teachings will also fall within the frame of gurmat. In any exigency, the decision to be taken by the followers must conform to gurmat in its ideological and/or conventional assumptions.