In ancient India, education was imparted in Gurukuls, and teachers were called Gurus. To translate the word Guru as teacher, would, however, be a gross misrepresentation. The Guru of ancient India not only imparted education to the kids but also stood as the symbol of knowledge in the society. The Guru was also the adviser to Kings and other people in the society. The concept of Guru in ancient India is beautifully depicted in this well known Sanskrit sloka:
Guru Brahma Gurur Vishnu
Guru Devo Maheshwaraha
Guru Saakshat Para Brahma
Tasmai Sree Gurave Namaha
Guru is verily the representative of Brahma, Vishnu and Shiva.
He creates, sustains knowledge and destroys the weeds of ignorance.
I salute such a Guru.
As time went by, the above verse met the same fate as that of many ancient things. The words remained, but the meaning was lost.