Gargi (गार्गी) is from the Sanskrit gotra-name Garga. Gargi Vachaknavi (c. 7th c. BCE) was the Vedic philosopher — one of the few women to debate at King Janaka's philosophical assembly. In the Brihadaranyaka Upanishad, she questioned the sage Yajnavalkya so deeply about the nature of the universe that he warned her not to ask further lest her head shatter. One of the most celebrated brahmavadinis (women who debated philosophy) of Vedic India.
Featured in the Brihadaranyaka Upanishad.
Gargi does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Gargi reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.