Unni in the Bible Encyclopedia - ISBE
un'-i (`unni, meaning unknown): (1) One of "the twelve
brethren" (so Curtis for the Revised Version (British and
American) "brethren of the second degree") appointed as
singers (1 Ch 15:18,20).
(2) In Neh 12:9 (Kethibh `unno) = the Revised Version (British
and American) UNNO (which see).
Read More about Unni in the Bible Encyclopedia - ISBE