From BiblePortal Wikipedia

Fausset's Bible Dictionary [1]

("two caverns".) Gave their name to a town of Moab ( Isaiah 15:5;  Jeremiah 48:3;  Jeremiah 48:5;  Jeremiah 48:34). On an eminence from which there was a "descent." Ptolemy's "Avara" is identified with Horonaim Sanballet, the opponent of the rebuilding of the Jerusalem wall ( Nehemiah 4:7;  Nehemiah 2:10), was an Horonite.

Hastings' Dictionary of the Bible [2]

HORONAIM (perh. ‘the two bollows’). A city of Moab, whose site has not been recovered with certainty. It is mentioned in   Isaiah 15:5 ,   Jeremiah 48:3;   Jeremiah 48:5;   Jeremiah 48:34 , and also on the Moabite Stone (11. 31, 32). It may have lain to the south of the Arnon, in the neighbourhood of the Wady ed-Derâ‘a .

Smith's Bible Dictionary [3]

Horona'im. (Two Caverns). A town of Moab, possibly a sanctuary, named with Zoar and Luhith.  Isaiah 15:5;  Jeremiah 48:3;  Jeremiah 48:5;  Jeremiah 48:34.

Morrish Bible Dictionary [4]

Place in Moab, mentioned by the prophets, with Zoar and Luhith.  Isaiah 15:5;  Jeremiah 48:3,5,34 . The name of Horonaim is found on the Moabite stone: it was taken by King Mesha.

Holman Bible Dictionary [5]

 Isaiah 15:5 Jeremiah 48:3 48:5 48:34

Easton's Bible Dictionary [6]

 Isaiah 15:5 Jeremiah 48:3,5,34

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [7]

(Heb. Chorona'yim, חֹרֹנִיַם , Two Caverns; Sept. Ἀρωνιείμ and ᾿Ωρωναϊ v Μ ), a Moabitish city near Zoar, Luhith, Nimrim, etc., on a declivity along the route of the invading Assyrians ( Isaiah 15:5;  Jeremiah 48:3;  Jeremiah 48:5;  Jeremiah 48:34); probably the same called Holon ( חֹלוֹן , perhaps by an error for חֹרוֹן , Horon, which would appear to be the original form of the word Horonaim; from חֹר , a Hole) in  Jeremiah 48:22 (Sept. Χελών ,Vulg. Helon). The associated names only afford a conjectural locality east of the north end of the Dead Sea, probably on some one of the great roads ( דֶּרֶךְ ) leading down from the plateau of Moab to the Jordan valley. It is doubtless the Oronse ( ᾿Ωρῶναι ) of Josephus (Ant. 13, 15, 4; 14, 1, 4). Sanballat "the Horonite" ( חֹרֹנַי ,  Nehemiah 2:10;  Nehemiah 2:19;  Nehemiah 13:28) was probably a native of this place, and not (as stated by Schwarz, Palestine, p. 147) of Beth- horon, which was entirely different.

International Standard Bible Encyclopedia [8]

hor - ō̇ - nā´im ( חרנים , חרונים , ḥōrōnayim  ; Ἀρωνιείμ , Arōnieı́m  ; in Jeremiah Ὀρωναίμ , Orōnaı́m , "the two hollows"): an unidentified place in the South of Moab. It is named in   Jeremiah 48:5 . Isaiah ( Isaiah 15:5 ) and Jeremiah ( Jeremiah 48:3 ) speak of "the way to Horanaim"; and Jeremiah ( Jeremiah 48:5 ) of the , "descent," or "going down" of Horonaim. Mesha (MS) says he was bidden by Chemosh to "go down" and fight against Ḥoronēm . Probably, therefore, it lay on one of the roads leading down from the Moabite plateau to the Arabah. It is mentioned by Josephus as having been taken by Alexander Janneus ( Ant. , Xiii , xv, 4). Hyrcanus promised to restore it and the rest to Aretas (XIV, i, 4). There is no indication that in early times it was ever possessed by Israel. Buhl ( GAP 272 f) thinks it may be represented by some significant ruins near Wādy ed - Derā‛a ( Wādy Kerak ).