Meaning of Waheguru
Different people have written different meanings of 'Waheguru'.
One is:
The word ‘Waheguru’ is combination of first character of the names by which god was called in different yugs (ages), i.e
W - Wishnu (Vishnu)
H - Hari
G - Gobind
R - Ram
As in gurbani each and every word has a meaning. Even if a word is spelled differently in Gurbani, has a different meaning. Gurbani is complete. We can not say: Even without this word the meaning of stanza (or line) will remain same and complete. Same way, except W,H,G,R the sounds aa( for WA), ae (for HE), u (for GU) and uu (for RU) must also have some meaning. The word 'Waheguru' has a deep meaning.
My guru, Sant Gurnam Singh Ji taught me, so I believe it.
WA = Wah = Wow = Astonishing
HE = Everywhere/Anywhere
GU = Dark
RU = Light
He taught me Waheguru is he who can illumine (anything) anywhere by vanishing dark in an astonishing manner.
Understanding technically:
To produce light one need a source, like electricity-electric bulb, fuel-flame, sun, etc. We need a SOURCE. We can not imagine light without a source. We can not produce it from nothing. But he can. So, the WA in Waheguru.
As he can produce light from nothing he can do it anywhere, as we do not require a specific conditions (or source). So, the HE in Waheguru.
Only one of GU or RU can exist. Once RU is produced GU will vanish.
Sarbat da bhala
Waheguru Ji Ka Khalsa
Waheguru Ji Ki Fateh
Tajinder Singh