The word Gurubani has been formed from two words Guru and Bani. While the word Guru can be used in various contexts, with a number of meanings, commonly the word Guru is used to refer to a wisely conscious mind. And, therefore, Gurubani is a reference to the speech of a wise mind.
Gurubani is basically a term used by the people of Sikh community and it refers to any of the spiritual compositions of the Sikh Gurus or the extracts of the Guru Granth Sahib. Gurubani in other words, people enchant to purify their mind and the body. In a nut shell we say that, the hymns extracted from the holy book Guru Granth Sahib of the Sikh community is called Gurubani. In addition to that, the Amritdhari Sikhs some of the texts extracted from Dasam Granth are also considered to be Gurubani.
Various spiritual scriptures advocate the fact that the sound of the Gurubani straightforwardly originates from the almighty and it connects us to the supreme power with the purity of every word of the text. It is also sometimes referred to as Gun Bani. Gurubani in very simple terms yet elaborately explains the qualities of the almighty which a human should try to inculcate in their own way of living. The point to be noted here is that, the writings that has existed in the history and other writings of the people from the Sikh community are not called Gurubani but Kachi Bani.