From BiblePortal Wikipedia

Hastings' Dictionary of the Bible [1]

KADMIEL . The name of a Levitical family which returned with Zerub. (  Ezra 2:40 =   Nehemiah 7:43; cf. 1Es 5:26 ). In   Ezra 3:9 (cf. 1Es 5:58 ), in connexion with the laying of the foundation of the Temple, as well as in   Nehemiah 9:4 f. (the day of humiliation) and   Nehemiah 10:9 (the sealing of the covenant), Kadmiel appears to be an individual. The name occurs further in   Nehemiah 12:8;   Nehemiah 12:24 .

Morrish Bible Dictionary [2]

A Levite and his family who returned from exile, and helped in the rebuilding of the temple. He led the devotions of the people and sealed the covenant.  Ezra 2:40;  Ezra 3:9 (see margin );  Nehemiah 7:43;  Nehemiah 9:4,5;  Nehemiah 10:9;  Nehemiah 12:8,24 .

Smith's Bible Dictionary [3]

Kad'mi-el. (Before God). One of the Levites who, with his family, returned from Babylon with Zerubbabel.  Ezra 2:40;  Nehemiah 7:43. He and his house are mentioned in history on three occasions -  Ezra 3:9;  Nehemiah 9:4-5;  Nehemiah 10:9. (B.C. 535-410).

Fausset's Bible Dictionary [4]

A Levite who returned with Zerubbabel ( Ezra 2:40;  Nehemiah 7:43): set forward the temple workmen, and joined in the thanksgiving at the laying of the foundation ( Ezra 3:9). His house took part in the general confession ( Nehemiah 9:4-5) and in the covenant ( Nehemiah 10:9).

Hawker's Poor Man's Concordance And Dictionary [5]

The name of one of the captives returned from Babylon. ( Ezra 2:40) If the word be derived, as it should seem likely to be, from Kadem, ancient, then is meant by Kadmiel, the ancient of God. Hence the Kadmonites, or ancient inhabitants of the east.

Holman Bible Dictionary [6]

 Ezra 2:40 Nehemiah 7:43  Ezra 3:9 Nehemiah 9:4-5 3 Nehemiah 10:9

Easton's Bible Dictionary [7]

 Nehemiah 9:4 10:9 12:8

International Standard Bible Encyclopedia [8]

kad´mi - el ( קרמיאל , ḳadhmı̄'ēl , "before God," "priest"(?); "Cadmiel" in parallel lists in 1 Esdras 5:26,58 the King James Version; omitted in Septuagint Codex Vaticanus; Codex Alexandrinus reads kaı̄ Kadmiḗlon ): A L evite ( Ezra 2:40;  Nehemiah 7:43 ), founder of a family whose descendants returned from captivity with Zerubbabel ( Ezra 2:1;  Nehemiah 7:43;  Nehemiah 12:1 ,  Nehemiah 12:8 ). He is named among those who praise God for the return ( Nehemiah 9:4 ,  Nehemiah 9:5;  Nehemiah 12:24 ); was of those who "set forward" the work of the Lord's house ( Ezra 3:9; 1 Esdras 5:26, 58), and is again mentioned with those who "seal" the new Return Covenant ( Nehemiah 10:28 ff) after the re-establishment of worship (  Nehemiah 10:1 ,  Nehemiah 10:9 ).

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [9]

(Heb. Kadmiel', קִדְמַיאֵל , Before God, I.E. his servant; Sept. Καδμιήλ ), one of the Levites who returned with Zerubbabel from the captivity ( Nehemiah 12:8), and assisted in the various reforms of that period, being always named in connection with Jeshua ( Ezra 3:9; Nehemiahvii, 43; comp.  Ezra 3:9); sometimes only as a descendant in common of Hodaviah ( Ezra 2:40;  Nehemiah 7:43; comp.  Ezra 3:9), but once as a son ( Nehemiah 12:24). The length of time over which these notices seem to extend (B.C. 536-410) leads to the suspicion that they relate to two individuals (perhaps a brother and also a son of the Levite Jeshua), one of whom may have been concerned in the earlier events, and the other in the later.