Kalliopi is from the Greek Kalliopē (Καλλιόπη) — kalli (beautiful) + ops (voice). Calliope is the eldest of the nine Muses in Greek mythology + the Muse of epic poetry — daughter of Zeus and Mnemosyne (Memory). 8th c. Central to Hesiod's Theogony.
Kalliopi 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 Kalliopi reduce to 4, The Builder. This is a traditional interpretive system, not a factual claim about the name.