Etta is the short form of Henrietta — itself the feminine of Henry/Henri, from the Germanic haimirich, meaning "home ruler" or "estate ruler." Etta James (1938-2012) gave the name eternal musical weight.
Etta has been rising fast as part of the vintage revival. Today Etta is in the U.S. top 700 and climbing.
Etta 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 Etta reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.