From BiblePortal Wikipedia

Fausset's Bible Dictionary [1]

Hebrew "the Ophel," i.e. the "swelling declivity" by which the temple hill slopes off on its southern side as a long round narrow promontory between the mouth of the Tyropeon central valley of the city and the Kedron valley of Jehoshaphat. On its eastern side is the fount of the Virgin; at the bottom is the lower outlet of the same spring, the pool of Siloam. Here was the "great tower" (Eder? Hebrew  Micah 4:8) and the Levites' residence. It was near the water gate ( Nehemiah 3:26-27;  Nehemiah 11:21). Jotham "built much on the wall of Ophel" Manasseh "compassed about Ophel" ( 2 Chronicles 27:3;  2 Chronicles 33:14); on the Ophla, as Josephus calls it (see B.J. 5:4, section 2; 6, section 1, 3). For "the forts" ( Isaiah 32:14). translated Ophel "the mound." James the Less was called Οblias , explained "bulwark of the people" (Hegesippus, in Eusebius H.E. ii. 23), perhaps originally Οphli-Am , from Ophel. He was martyred by being thrown from the temple pinnacle near the boundary of Ophel.

Smith's Bible Dictionary [2]

O'phel. (Hill). A part of ancient Jerusalem. Ophel was the swelling declivity, by which the mount of the Temple slopes, on its southern side into the valley of Hinnom - a long, narrowish rounded spur or promontory, which intervenes between the mouth of the central valley of Jerusalem, (the Tyropoeon), and the Kidron, or valley of Jehoshaphat.

Halfway down it, on its eastern face is the, "Fount of the Virgin," so called; and at its foot the lower outlet of the same spring - the Pool of Siloam. In  2 Chronicles 27:3, Jotham is said to have built much, "on the wall of Ophel." Manasseh, among his other defensive works, "compassed about Ophel." Ibid.  2 Chronicles 33:14. It appears to have been near the "water-gate,"  Nehemiah 3:26, and the "great tower that lieth out."  Nehemiah 3:27. It was evidently the residence of the Levites.  Nehemiah 11:21.

American Tract Society Bible Dictionary [3]

A quarter of Jerusalem adjacent to the temple, and therefore occupied by the Nethinim,  Nehemiah 3:26,27   11:21 . It appears to have been enclosed by a wall, and fortified by a strong tower,  2 Chronicles 27:3   33:14; and is thought to be meant by the Hebrew  Micah 4:8 . There can be little doubt that the name belongs to the lower ridge into which Mount Moriah sinks, south of the area of the mosque. It is one hundred yards wide, and extends six hundred yards to the south, terminating in a bluff forty or fifty feet high above the pool of Siloam. It is separated from Mount Zion on the west by the valley called Tyropoeon, and is now devoted to the culture of olives, figs, and other fruit.

Morrish Bible Dictionary [4]

A part of Jerusalem, first mentioned in  2 Chronicles 27:3 , where it is said that Jotham built much "on the wall of Ophel." Manasseh in his building, "compassed about Ophel and raised it up a very great height.'  2 Chronicles 33:14 . On the return from exile the Nethinim dwelt there.  Nehemiah 3:26,27;  Nehemiah 11:21 . It is supposed to have been at the S.E. corner of Jerusalem, outside the present walls, near the Virgin's fountain. The same word is translated 'tower' in  2 Kings 5:24 , as in the margin of some of the above passages.

People's Dictionary of the Bible [5]

Ophel ( Ô'Fel ), Hill, Swelling. A hill of ancient Jerusalem and fortified by a wall.  2 Chronicles 27:3;  2 Chronicles 33:14;  Nehemiah 3:26-27;  Nehemiah 11:21, but it is now outside the walls of the city. See Jerusalem.

Holman Bible Dictionary [6]

 2 Chronicles 27:3 Nehemiah 3:26-27 Nehemiah 4:8 Isaiah 32:14 2 Kings 5:24

Easton's Bible Dictionary [7]

 2 Chronicles 27:3 33:14 Nehemiah 3:26,27 Isaiah 4  2 Kings 5:24

Hawker's Poor Man's Concordance And Dictionary [8]

The name of a wall in the house of the Lord. ( 2 Chronicles 27:3)

Hastings' Dictionary of the Bible [9]

OPHEL. See Jerusalem, II. § 1, 2.

International Standard Bible Encyclopedia [10]

ō´fel ( העפל , ha - ‛ōphel (  2 Chronicles 27:3;  2 Chronicles 33:14;  Nehemiah 3:26 f;   Nehemiah 11:21; and without article,  Isaiah 32:14 and   Micah 4:8; also  2 Kings 5:24 )):

1. Meaning of Name:

There has been considerable divergence of opinion with regard to the meaning of this name. Thus, in all the references given above with the article, the Revised Version (British and American) has simply "Ophel," but the King James Version adds in margin "the tower"; in  Isaiah 32:14 , "the hill" with margin "Ophel," but the King James Version "the forts," margin "clifts";  Micah 4:8 , "the hill," margin "Hebrew: Ophel," but the King James Version "the stronghold";  2 Kings 5:24 , "the hill," margin "Hebrew: Ophel," but the King James Version "the tower," margin "secret place." It is true that the other occurrences of the word in  1 Samuel 5:9 ,  1 Samuel 5:12;  1 Samuel 6:5 f, where it is translated "tumors," and   Habakkuk 2:4 , where a verbal form is translated "puffed up," seem to imply that one meaning assigned to the root may be that of "swelling." Recently Dr. Burney ( PEF , January, 1911) has produced strong arguments in favor of Ophel, when used as the name of a locality, meaning "fortress."

2. Three Ophels:

Three places are known to have received this name: (1) A certain place on the east hill of Jerusalem, South of the temple; to this all the passages quoted above - except one - refer. (2) The "Ophel," translated "hill," situated apparently in Samaria (compare  2 Kings 5:3 ), where Gehazi took his ill-gotten presents from the hands of the servants of Naaman the Syrian. The translation "tower" would suit the sense at least as well. It was some point probably in the wall of Samaria, perhaps the citadel itself. (3) The third reference is not Biblical, but on the Moabite Stone, an inscription of Mesha, king of Moab, contemporary with Omri. He says: "I built ḲRḤH (? Karhah), the wall of ye‛ārı̄m , and the wall of 'Ophel and I built its gates and I built its towers." In comparing the references to (1) and (3), it is evident that if Ophel means a "hill," it certainly was a fortified hill, and it seems highly probable that it meant some "artificial swelling in a fortification, e.g. a bulging or rounded keep or enceinte" (Burney, loc. cit.).  Isaiah 32:14 reads, "The palace shall be forsaken; the populous city shall be deserted; the hill (Ophel) and the watch-tower shall be for dens for ever." Here we have palace, city and watch-tower, all the handiwork of the builder. Does it not seem probable that the Ophel belongs to the same category?

3. The Ophel of Jerusalem:

The situation of the Ophel of Jerusalem is very definitely described. It was clearly, from the references ( Nehemiah 3:26 ,  Nehemiah 3:27;  2 Chronicles 27:3;  2 Chronicles 33:14 ), on the east hill South of the temple. Josephus states (Josephus, Jewish Wars , V, iv, 2) that the eastern wall of the city ran from Siloam "and reaches as far as a certain place which they called Ophlas when it was joined to the eastern cloister of the temple." In BJ , V, vi, 1, it states that "John held the temple and the parts thereto adjoining, for a great way, as also 'Ophla,' and the Valley called the 'Valley of the Cedron.' " It is noticeable that this is not identical with the "Acra" and "Lower City" which was held by Simon. There is not the slightest ground for applying the name Ophel, as has been so commonly done, to the whole southeastern hill. In the days of Josephus, it was a part of the hill immediately South of the temple walls, but the Old Testament references suit a locality nearer the middle of the southeastern hill. In the article Zion (which see) it is pointed out that that name does not occur (except in reference to the Jebusite city) in the works of the Chronicler, but that "the Ophel," which occurs almost alone in these works, is apparently used for it.  Micah 4:8 margin seems to confirm this view: "O tower of the flock, the Ophel of the daughter of Zion." Here the "tower of the flock" may well refer to the shepherd David's stronghold, and the second name appears to be a synonym for the same place.

Ophel then was probably the fortified site which in earlier days had been known as "Zion" or "the City of David." King Jotham "built much" "on the wall of Ophel" ( 2 Chronicles 27:3 ). King Manasseh "built an outer wall to the city of David, on the west side of Gihon, in the valley, even to the entrance at the fish gate; and he compassed Ophel about with it, and raised it up to a very great height" ( 2 Chronicles 33:14 ). It was clearly a fortified place of great importance, and its situation must have been so near that of the ancient "Zion" that scarcely any other theory is possible except that it occupied the site of that ancient fortress.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [11]

(Heb. always with the article, ha-O'phel, הָעֹפֵל ,The Knoll, as in Micah 4, 8 Sept. ᾿Ωφάλ ,  Nehemiah 3:26; Ο᾿Φλά ,  Nehemiah 3:27; v. r. Ο᾿Πελ , Ο᾿Πλά ; Vulg. Ophel), the name of two places in Palestine.

1. A fortified place or quarter of Jerusalem near the walls ( 2 Chronicles 27:3), on the east side, inhabited by the Nethinim after the rebuilding of the city ( Nehemiah 3:26;  Nehemiah 11:21). Ophel, or as he calls it; Ophla ( Οο῾᾿Φλά ), is often mentioned by Josephus as adjoining the valley of the Kidron and the Temple mount ( War, 2:17, 9; 5. 6, 1). He explains himself more precisely in v. 4, 2, where he makes the first wall of the city to extend from the tower of the Essenes over Siloam and the pools of Solomon to Ophel, where the latter joins the eastern porch of the Temple, i.e. at its southern extremity. Hence there can be no doubt that the hill Ophel was the steep southern projection from the mountain on which the Temple stood, aid that in the ancient city it was covered with houses (Josephus, War, v. 6, 3). Dr. Robinson (Bibl. Res. 1:394) describes it as a ridge extending south from Moriah to Siloam, between the deep valley of Jehoshaphat on the east, and the steep but shallower Tyropoeon valley on the west. The top of this ridge is flat, descending rapidly towards the south, sometimes by Offsets of rocks; and the ground is now tilled and planted with olive and other fruit trees. This ridge is considerably below the level of Mount Moriah; its length is 1550 feet, and its breadth in the middle part, from brow to brow, 290 feet. The excavations of the English engineers have shown that it was originally separated from Moriah by a considerable gully, but the ancient wall has been discovered joining it with the Temple near the south-east angle. (See Jerusalem).

2. A place in Central Palestine, in which was the house where Gehazi, Elisha's servant, stowed away the presents which he took from Naaman in the name of his master ( 2 Kings 5:24). (See Gehazi); (See Naaman). In the Auth. Vers. it is wrongly rendered "the tower;" margin, "the secret place," after the Sept. ( Τὸσκοτεινόν ) . As the name means Hill, it is probably here the name especially of an elevation in the immediate vicinity of the city of Samaria. Comp. Viervot, Bibl. Brem. Nov. 2:137 sq.

Kitto's Popular Cyclopedia of Biblial Literature [12]

O´phel, a place or quarter of Jerusalem near the walls , on the east side . From the intimations regarding it given by Josephus, Winer collects that Ophel was a high or ascending place, built over (in the ancient city) with houses. This view is confirmed by Dr. Robinson, who identifies it with the low ridge which extends southward from the temple mount to Mount Zion, between the exterior valley of Jehoshaphat and the interior valley of Tyropeon. This ridge is considerably below the level of Mount Moriah; its length is 1550 feet, and its breadth in the middle part, from brow to brow, 290 feet [JERUSALEM].