The word ‘Satsanga’ is the combination of the two words ‘Sat’ and ‘Sanga.’ ‘Sat’ means existence absolute, which is Brahman. ‘Sat’ is the essential nature of Brahman which is permanent in things that change, which is the only reality that upholds the world of appearance.
The same ‘Sat,’ with the accidental attributes of omnipresence, omniscience and omnipotence is called Isvara or Paramatman. In brief, ‘Sat’ refers to Isvara as well as Brahman, both ultimately being the one and the same reality.
‘Sanga’ literally means company or union. To be always in the company of the Lord, or to be established in Brahman, is the literal meaning of the word ‘Satsanga.’ But, as long as ignorance or Avidya remains, the direct realisation of Brahman is impossible. When ignorance is destroyed by wisdom, the real nature reveals itself. This is the highest Satsanga.
The next possibility is to please God so much by our unflinching devotion that He has to sport with us assuming a gentle form according to our desire, even as He did in the case of the Gopis. But the means to the realisation of this blessed end is also called Satsanga or the company of the wise. The means being essentially not different from the end, is also named after the end. Because the company of the wise leads to the realisation of Brahman (with attributes or without attributes), it is also termed as Satsanga. In this sense, Satsanga means the company of the Satpurushas. Satpurushas are those who have realised truth as well as those who are aspirants after truth. Those people who have renounced egoism, greed, lust, etc., are Satpurushas. Those people who have attained equal vision, balanced mind, unflinching devotion to the Lord, are Satpurushas. Those people who are endowed with peace, bliss, contentment, simplicity, fearlessness, humility, powerful voice, a face beaming with the glow of saintliness, etc., are Satpurushas.