From BiblePortal Wikipedia

Hawker's Poor Man's Concordance And Dictionary [1]

A valley in Jericho: rendered memorable from the stoning of Achan, the son of Carmi, there. Indeed the valley seems to have borrowed its name from this man. See the history ( Joshua 7:17-26) The margin of the Bible at the last verse so explains. Achor means trouble. It is somewhat remarkable, that one so injurious to Israel should have been born called Achan, as if from his birth ordained to this condemnation. ( Jude 1:1:4) I know not whether I should have noticed this valley, or the history of Achan, to whom it refers, had it not been from the gracious use the Lord makes of it, in a way of figure, by allusion, in promising happier times to Israel. ( Hosea 2:15) In this sweet chapter, the Lord is following up his rich promises of grace, in return for Israel's repeated ingratitude and rebellion. But grace shall triumph. For, saith the Lord, from trouble like that of Achan, I will raise up comfort to my people: when from the sorrows induced by sin, under the quickening convictions for sin, and the exercises wrought in the soul, by the power of the Holy Ghost, I will bring my people into the blessed consolations of deliverance by Christ. "And I will give her her wine-yards from thence; and the valley of Achor for a door of hope: and she shall sing there as in the days of her youth, and as in the day when she came up out of the land of Egypt." ( Isaiah 65:10)

People's Dictionary of the Bible [2]

Achor ( Â'Kor ), Trouble. A valley near Jericho, where Achan was stoned; and from the trouble Achan brought upon Israel it had its name.  Joshua 7:24;  Joshua 7:26. Yet from that trouble sanctified a new career of victory began. With this idea we find the place and the circumstance afterwards adverted to.  Hosea 2:15. The valley of trouble was the door through which Israel entered Canaan first; and again through the valley of trouble would the Lord lead his ransomed people to peace and rest. The boundary line of Judah ran by Achor.  Joshua 15:7. It is also mentioned in  Isaiah 65:10.

Hastings' Dictionary of the Bible [3]

ACHOR ( ’çmeq ’âkhôr , ‘Vale of Grief’). Here Achan (wh. see), with his family, was stoned to death. It lay on the boundary between Judah and Benjamin (  Joshua 15:7 etc.). Guthe identifies it with the plain south of Jericho, between the mountains on the west, and Jordan and the Dead Sea on the east. Wâdy Kelt , a tremendous gorge which breaks down from the mountain W. of Jericho, probably formed the boundary between Judah and Benjamin. In the mouth of this valley, it seems likely, the execution took place.

W. Ewing.

Wilson's Dictionary of Bible Types [4]

 Joshua 7:24 (c) This valley represents a place of sorrow and trouble in human lives. As Achan was stoned there, and his sin put away, so in our lives times of trouble and sorrow may be called "the place of Achor." There GOD's remedy is to be applied to the difficulty.

 Hosea 2:15 (c) The valley in this passage is described as a door of hope. When sin is judged and put away, then hope for GOD's blessing is revived, and joy replaces sorrow.

American Tract Society Bible Dictionary [5]

Trouble, a valley north of Jericho; so called, perhaps, from the troubles occasioned by the sin of Achan, who was here put to death,  Joshua 7:26 . The prophets allude to it with promises of hope and joy in the gospel era,  Isaiah 65:10;  Hosea 2:15 .

King James Dictionary [6]

A'CHOR, n. Gr., sordes capitis.

1. The scald head, a disease forming scaly eruptions, supposed to be a critical evacuation of acrimonious humors a species of herpes. 2. In mythology, the God of flies, said to have been worshipped by the Cyreneans, to avoid being vexed by those insects.

Holman Bible Dictionary [7]

 Joshua 7:24-26 Isaiah 65:10  Hosea 2:15Joshua

Easton's Bible Dictionary [8]

 Joshua 7:24,26 Isaiah 65:10 Hosea 2:15

Watson's Biblical & Theological Dictionary [9]

Valley of, between Jericho and Ai. So called from the trouble brought upon the Israelites by the sin of Achan; Achor in the Hebrew denoting trouble.

Fausset's Bible Dictionary [10]

On the northern boundary of Judah ( Joshua 15:7). (See Achan .)

International Standard Bible Encyclopedia [11]

ā̄´kor ( עכור , ‛ākhō̄r , "trouble," the idea of the word being that of trouble which is serious and extreme. See Achan ): The place where Achan was executed in the time of Joshua ( Joshua 7:24 ,  Joshua 7:26 ). In all the five places where it is mentioned it is described as the ‛ēmek , the arable valley of Achor. There is no ground in the record for the current idea that it must have been a locality with horrid and dismal physical features. It was on a higher level than the camp of Israel in the Jordan valley, and on a lower level than Debir - a different Debir from that of  Joshua 15:15 . In a general way, as indicated by the points mentioned in the border of Judah, it was north of Betharabah, and south of Debir ( Joshua 7:24;  Joshua 15:7 ). Many identify it with the Wady Kelt which descends through a deep ravine from the Judean hills and runs between steep banks south of the modern Jericho to Jordan, the stream after rams becoming a foaming torrent. Possibly the name may have been applied to a region of considerable extent. In  Isaiah 65:10 it is a region on the east side of the mountain ridge which is in some sense balanced with Sharon on the west side. By implication the thing depicted seems to be these rich agricultural localities so far recovered from desolation as to be good grounds for cattle and sheep. Hosea recognizes the comforting aspect of the dreadful affair in the valley of Achor; it was a doorway of hope to pardoned Israel (  Hosea 2:15 (  Hosea 2:17 )), and he hopes for like acceptance for the Israel of his own day.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [12]

(Heb. Akor', עָכוֹר , Trouble; Sept. Ἀχωρ ), the name of a valley ( עֵמֶק , Sept. Φάραγξ , Κοιλάς , E Μεκ ) not far from Jericho, given in consequence of the trouble occasioned to the Israelites by the sin of Achan

(q.v.), who was stoned to death and buried there ( Joshua 7:24;  Joshua 7:26). It was known by the same name in the time of Jerome (Onomast. s.v.). The prophets more than once allude to it typically in predicting the glorious changes under the Messiah, either on account of its proverbial fertility ( Isaiah 65:10) or by way of contrast with the unfortunate entrance of the Israelites near this pass into Canaan on their first approach ( Hosea 2:15). It was situated on the boundary of Judah and Benjamin, between the stone of Ben-Bonan and Debir, south of Gilgal ( Joshua 15:7), and was probably the same now called (see Zimmerman's Map) Wady Dabr, running into the Dead Sea east of Ain Jehair (Robinson's Researches, 2, 254). (See Tribe). Thomson (Land And Book, 2, 185) says vaguely that "it runs up from Gilgal toward Bethel;" but this is inconsistent with the above notices of location (comp. Keil, Comment. On Joshua p. 201). (See Cherith).

Kitto's Popular Cyclopedia of Biblial Literature [13]

A´chor, a valley between Jericho and Ai, which received this name (signifying trouble) from the trouble brought upon the Israelites by the sin of Achan ( Joshua 7:24) [ACHAN].