ef’-od (‘ephowdh (28 times), ‘ephodh (20 times), ‘ephodh; Septuagint epomis, ephoth, ephod, ephoud, stole exallos, stole bussine):
(1) A sacred vestment originally designed for the high priest (Exodus 28:4; 39:2), and made “of gold, blue, and purple, and scarlet, and fine twined linen,” held together by two shoulder-pieces and a skillfully woven band which served as a girdle for the ephod. On the shoulderpieces were two onyx stones on which were engraved the names of the twelve tribes of Israel. It is not known whether the ephod extended below the hips or only to the waist. Attached to the ephod by chains of pure gold was a breastplate containing twelve precious stones in four rows. Underneath the ephod was the blue robe of the ephod extending to the feet of the priest. The robe of the ephod was thus a garment comprising, in addition to the long robe proper, the ephod with its shoulderpieces and the breastplate of judgment.
(2) From the historical books we learn that ephods were worn by persons other than the high priest. Thus, the boy Samuel was girded with a linen ephod while assisting the aged high priest (1 Samuel 2:18); the priests at Nob, 85 in number, are described as men wearing a linen ephod (1 Samuel 22:18); and David was girded with a linen ephod when he danced in the procession that brought the ark into Jerusalem (2 Samuel 6:14). The ephod was considered appropriate for the king on this solemn and happy occasion; but it would be reading into the narrative more than it contains to infer that lay worshippers were regularly clothed with the ephod; nor are we to suppose that priests other than the high priest were accustomed to wear ephods as rich and elaborate as that of the high priest. Abiathar, who became high priest after the assassination of his father by Doeg, probably brought to the camp of David the ephod worn by the high priest in his ministrations at Nob (1 Samuel 23:6), and through this ephod David sought in certain crises to learn Yahweh’s will (1 Samuel 23:9; 30:7). Some have argued that the ephod, which Abiathar brought in his hand, was an image rather than a priestly garment, but there seems no sufficient reason for regarding it as other than a vestment for the high priest. The ephod behind which the sword of Goliath was kept wrapped in a cloth may well have been a garment suspended from the wall or itself wrapped in a protecting cloth (1 Samuel 21:9).
(3) The ephod mentioned in Judges 17:5; 18:14; Hosea 3:4 is associated with teraphim and other idolatrous images. We may frankly confess that we do not know the shape, size and use of the ephod in these cases, though even here also the ephod may well have been a priestly garment. The same remark holds good of the ephod made by Gideon, and which became an object of idolatrous worship in Israel (Judges 8:27). It has been argued that a vestment would not cost seventeen hundred shekels of gold. Possibly Gideon set up an apparatus of worship containing other articles just as the mother of Micah began with the promise to make a graven image and a molten image, and afterward added an ephod and teraphim (Judges 17:1-5). Moreover, if gems and brilliants were put on Gidcon’s ephod, who can say that it did not cost seventeen hundred shekels?
[Source: Orr, James, M.A., D.D. General Editor. “Entry for ‘EPHOD (1)'”. “International Standard Bible Encyclopedia”. 1915]