Boyd’s Bible Dictionary:

(doubly fruitful). (1) Second son of Joseph (Gen. 41:52). Obtained Jacob’s blessing (Gen. 48:8-20). Tribe numerous (Num. 1:33; 26:37). Allotment as in Joshua 16:1-10. (2) Site of Absalom’s sheep-farm (2 Sam. 13:23). (3) Place to which Christ retired (John 11:54). (4) A gate of Jerusalem (2 Kings 14:13; 2 Chron. 25:23; Neh. 8:16; 12:39). (5) “Mount of,” in Ephraim (1 Sam. 1:1). (6) The “wood of,” east of Jordan (2 Sam. 18:6).

Concise Bible Dictionary:

Second son of Joseph and Asenath. The name is also given to the tribe of which he was the head, and also to the district of Palestine that fell to his lot. When Israel blessed the two sons of Joseph he set Ephraim before his elder brother, saying he should be greater, and his seed should become a multitude (or, “fatness”) of nations (Gen. 48:17-19). Little is recorded of Ephraim personally; and of his descendants, Joshua the son of Nun is the most renowned. The tribe on the second year from the Exodus numbered in fighting men 40,500; but had decreased during the forty years to 32,500 (Num. 1:33; Num. 26:37).
The territory of the tribe was in the heart of Palestine, having Manasseh on the north, Benjamin on the south, and Dan on the west. See the map under TWELVE TRIBES. It has beautiful valleys and noble mountains with many springs and streams. Its two principal towns were Shiloh and Shechem.
Ephraim had the place of the first-born (Jer. 31:9), the birthright being taken from Reuben and given to Joseph (1 Chron. 5:1-2). Also the place of the tabernacle was in the tribe of Ephraim, hence we find in the time of the judges this tribe asserting its own importance. They were angry with Gideon for not calling them to the war sooner than he did; but a soft answer appeased their wrath (Judg. 7:24; Judg. 8:1-3). Again they complained to Jephthah that he had gone without them to fight the Ammonites, though Jephthah declared that he had called them, and they had not responded. They also haughtily said of the Gileadites that they were fugitives of Ephraim, implying that they were not a tribe, but belonged to Ephraim, from whence they had escaped. The conflict was sharp; the Gileadites seized the ford of the Jordan, and then by putting all who wanted to pass to the test of pronouncing Shibboleth (which the Ephraimites could only call Sibboleth) they slew 42,000 of the men of Ephraim (Judg. 12:1-6). Thus was this proud and envious tribe punished for molesting their brethren, whereas they had not driven out the heathen inhabitants of the land, as they should have done (Judg. 1:29). Type of many in the church who in pride contend with their brethren, but do not fight God’s battles against spiritual wickedness. Later on the Lord forsook Shiloh, and chose, not the tribe of Ephraim, but that of Judah both for the place of royalty and for the sanctuary.
In the kingdom under David and Solomon we read very little of Ephraim, but it is twice called in the Psalm “the strength (or defense) of mine head” (Psa. 60:7; Psa. 108:8). At the division of the tribes Ephraim took the most prominent place; Shechem and Samaria being in their territory naturally contributed to this, and accounts for the ten tribes being constantly called “Ephraim” by the prophets. In the same way the two tribes are called “Judah” (Hos. 5:3, 5, 13-14, &c). Isaiah prophesied that in sixty-five years Ephraim should be broken and should not be a people (Isa. 7:8). This was in B.C. 742, and Samaria was taken and Israel carried into captivity in B.C. 721, so that the prophecy doubtless referred to Esarhaddon planting a colony of foreigners in Samaria in B.C. 678, which fulfills the sixty-five years. This also agrees with the prophecy saying “the head of Ephraim” is Samaria.
In the prophecies also that refer to the future blessing of the twelve tribes Ephraim is regarded as representing the ten tribes (Ezek. 37:16-22), where the twelve tribes are to become one nation in their own land, with one king over them: a prophecy which clearly has never yet been fulfilled, but which will surely be accomplished in God’s own time.

Jackson’s Dictionary of Scripture Proper Names:

double ash-heap: I shall be doubly fruitful