Madri (माद्री) means "of the Madra kingdom." The Madra princess who became Pandu's second wife in the Mahabharata — mother of the youngest Pandavas Nakula and Sahadeva (begotten by the Ashvini twin gods through Kunti's mantra).
Madri 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 Madri reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.