Meshullemeth (מְשֻׁלֶּמֶת) means "friend" or "reconciled" in Hebrew. In 2 Kings 21:19, Meshullemeth was the mother of King Amon of Judah — daughter of Haruz of Jotbah. Grandmother of Josiah the reformer king.
Among the most obscure named Judahite queen-mothers.
Meshullemeth 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 Meshullemeth reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.