History of its adoption
On December 1, 1880, the Founders went to Allâhâbâd to visit Mr. and Mrs. Sinnett. Two days later, Col. Olcott left for Benares to stay as a guest of the Mahârâja. Mme. Blavatsky joined him on the 11th.
The family motto of the Maharaja of Benares was Satyan nasti paro dharmah, which is a somewhat modified passage from the Mahâbhârata (Sântiparvan, chap. 160, stanza 24)
The motto is an English translation of the Sanskrit phrase, one word of which has special meanings that shed light on the whole motto. The original Sanskrit is Satyan nasti paro dharmah, which might also be translated as “Nothing is greater than truth.” The first three words can be literally translated thus: satyan “than truth,” nasti “is not,” paro “further, greater, higher.” Dharmah is difficult to translate because it means so many things. Its root meaning is “what is established or firm.” And from that basic root sense radiate such other meanings as “law,” “customs,” “duty,” “morality,” “justice,” “religion,” “teachings or doctrine,” “good works,” and “essential nature.”
The motto is not specifically about what we think of as religion. Instead it is saying that none of our commitments or social conventions or ideas can measure up to the reality of what truly is. Reality is greater than any of its parts and is beyond all our notions about it. In saying that, the motto at the bottom of the seal directs our attention back to the word Om at the top. That word is a symbol of what truly is, of Truth. And so the whole seal, just like the serpent, ends where it began—affirming the supreme Truth that unites all things.