3 occurrences in 3 dictionaries
Reference: Bakbuk
Hastings
The ancestor of certain Nethinim who returned with Zerubbabel (Ezr 2:51; Ne 7:53); called Acub in 1Es 5:31.
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Smith
Bak'buk
(bottle). "Children of Bakkuk" were among the Nethinim who returned from captivity with Zerubbabel.
(B.C. before 536).