2 occurrences in 2 dictionaries
Reference: Regemmelech
Morish
Re'gem-mel'ech
One sent unto the house of God, in the time of Darius, to pray and to consult with the priests and prophets respecting the continuation of fasting in the fifth month. Zec 7:2. This fast had probably been observed in commemoration of the destruction of Solomon's temple. 2Ki 25:8-9. God's answer, through Zechariah, was that they had not fasted to Him: it was insincerity on their part.
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Smith
Re'gem-me'lech
(friend of the king). The names of Sherezer and Regem-melech occur in an obscure passage of Zechariah.
They were sent on behalf of some of the captivity to make inquiries at the temple concerning fasting (B.C. 617.)