From BiblePortal Wikipedia

Hastings' Dictionary of the Bible [1]

Horonite (  Nehemiah 2:10;   Nehemiah 2:19;   Nehemiah 13:28 ). A title given to Sanballat (wh. see), the opponent of Nehemiah. The name probably denotes an inhabitant of Beth-boron (wh. see).

Morrish Bible Dictionary [2]

Designation of Sanballat, probably as a native of Horonaim or of Beth-horon.  Nehemiah 2:10,19;  Nehemiah 13:28 .

Easton's Bible Dictionary [3]

 Nehemiah 2:10,19 Joshua 16:3,5

Holman Bible Dictionary [4]

 Nehemiah 2:10

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [5]

[many Hor'onite] (Heb. with the art. ha-Clhoroni', הִחֹרֹנַי ; Sept. Οα῾᾿Ρωνί , Οὐρανίτης , Vulg. Horonites), the designation of Sanballat (q.v.), who was one of the principal opponents of Nehemiah's works of restoration ( Nehemiah 2:10;  Nehemiah 2:19;  Nehemiah 13:28). It is derived by Gesenius (Thes. p. 459) from Horonaim, the Moabitish town, but by Furst (Handw.) from Horon, i.e. Bethhoron. The latter supposition agrees with the local relations of Sanballat towards the Samaritans, but the former suits better his heathenish affinities, as well as the simple form of the primitive.

International Standard Bible Encyclopedia [6]

hor´ō̇ - nı̄t , hō´rō̇ - nı̄t ( החרני , ha - ḥōrōnı̄ ): an appellation of Sanballat (  Nehemiah 2:10 ,  Nehemiah 2:19;  Nehemiah 13:28 ), as an inhabitant of Beth-Horon (which see).