Sigourney is a 20th-century American invention — chosen by actress Susan Alexandra Weaver as her stage name at age 14, taken from the character Sigourney Howard in The Great Gatsby (1925) by F. Scott Fitzgerald. Yale School of Drama (MFA, 1974).
Subject of countless science-fiction histories.
Sigourney 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 Sigourney reduce to 7, The Seeker. This is a traditional interpretive system, not a factual claim about the name.