From BiblePortal Wikipedia

Smith's Bible Dictionary [1]

Na'um. (Consolation). Son of Esli, and father of Amos, in the genealogy of Christ ,  Luke 3:25, about contemporary, with the high priesthood of Jason, all the reign of Antiochus Epiphanes. (B.C.175).

Morrish Bible Dictionary [2]

Son of Esli in the genealogy of the Lord Jesus.  Luke 3:25 .

Holman Bible Dictionary [3]

 Luke 3:25

Fausset's Bible Dictionary [4]

 Luke 3:25.

International Standard Bible Encyclopedia [5]

nā´um  : the King James Version form, Nahum (which see), the name of an ancestor of Jesus ( Luke 3:25 ).