Indigo comes from the Greek indikon, meaning "Indian" — referring to the deep blue dye originally imported from India. The color is one of the seven that Isaac Newton named in the visible spectrum.
Indigo entered the U.S. top 1000 as a girls' name in 2020.
Indigo 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.
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In Pythagorean numerology the letters of Indigo reduce to 4, The Builder. This is a traditional interpretive system, not a factual claim about the name.