Oanh is from the Vietnamese Oanh (鶯 — oriole). Oanh is one of the Vietnamese feminine names — central to traditional Vietnamese poetic bird-naming heritage appearing in Nguyễn Du's Truyện Kiều (1820).
Oanh 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 Oanh reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.