NO its NOT a Name for Guru Gobind Singh ji or any other Guru Sahib, Bhagat Sahib Ji or anything like that. It Means..OH WONDERFUL GURU !! and was first used by the BHATTS to describe the way they felt when they had darshan of Guru Ramdass Ji.....ALL they could say was..WAHEGURU...WAHEGURU...WAHEGURU..WAHEGURU...WA HEGURU...
WAHEGURU...WAHEGURU...WAHEGURU....WAHE JIO.... THIS is the ONE and ONLY TIME this word occurs in the entire 1429 pages of Sri Guru Granth Sahib Ji.
Bhai Gurdass Ji in his Vaar..is simply being POETIC..and using his poetic LICENSE....as often happens even TODAY....when we have WORDS manufactured out of Beginning Alphabets of a Word....SIR... S
esident...and its also highly possibke that this Vaar is NOT by Bhai Gurdass Ji at all but a later interpolation/adulteration/addition by a Vedanta beleiver..simply becasue the Vaars and other literature has coem down to us via THIRD PARTIES who are NOT SIKHS..but Udasis, Nirmalas, and descendnats of those who were REJECTED as GURUS by the Guru sahibaans...these are the Sons of Guru Nanak Ji, Guru Angad Ji, Guru Amardass Ji, Guru ramdass Ji...etc etc...THESE had a vested interest in adulterating sikh literary works.Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=8193Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=8193
The Guru Khalsa Panth NOW ACCEPTS this word WAHEGURU for AKAL PURAKH. Its the Gurmantar given by the Panj Piayaras at Pahul time and is also part of the Khalsa FATEH. So no one should DOUBT its importance in Gurmatt/Sikhi - its now inseparable form the Khalsa...and a part of the daily Nitnem, Greeting ardass etc.