Indu (इन्दु) is the Sanskrit word for "moon" — also referring to a bright droplet, such as a dewdrop.
Indu is widely used in India.
Indu 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 Indu reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.