The meaning of the word, Guru (Spiritual master), is very grave. If the word is analyzed it’s only two parts ‘Gu’ and ‘ru’ are obtained. Here ‘Gu’ signifies ‘Darkness’ and ‘ru’ means ‘Light’. It simply indicates that he who is able to save forever illusioned persons from the clutches of darkened maya (illusion) and is able to make them reach the sun or light-like God will be considered to be described as a ‘Guru’.
Srila Bhakti Bibudha Bodhayan Maharaj