Morrigan (An Mórrígan) is the Irish goddess of war, fate, and sovereignty — a shape-shifter who often appears as a crow or raven.
Morrigan is rising slowly as a girls' name — chosen by parents drawn to dark Celtic mythological weight.
Morrigan 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 Morrigan reduce to 5, The Seeker. This is a traditional interpretive system, not a factual claim about the name.