'Êphôd (אֵפֹד, Strong's #646), “ephod.” This word, which appears in Assyrian and (perhaps) Ugaritic, occurs 49 times in the biblical Hebrew, 31 times in the legal prescriptions of Exodus—Leviticus and only once in biblical poetry (Hos. 3:4).
This word represents a close-fitting outer garment associated with worship. It was a kind of long vest, generally reaching to the thighs. The “ephod” of the high priest was fastened with a beautifully woven girdle (Exod. 28:27-28) and had shoulder straps set in onyx stones, on which were engraved the names of the twelve tribes. Over the chest of the high priest was the breastplate, also containing twelve stones engraved with the tribal names. Rings attached it to the “ephod.” The Urim and Thummin were also linked to the breastplate.
Apparently, this “ephod” and attachments were prominently displayed in the sanctuary. David consulted the “ephod” to learn whether the people of Keilah would betray him to Saul (1 Sam. 23:9-12); no doubt the Urim and Thummim were used. The first biblical occurrence of the word refers to this high priestly ephod: “Onyx stones, and stones to be set in the ephod, and in the breastplate” (Exod. 25:7). So venerated was this “ephod” that replicas were sometimes made (Judg. 8:27; 17:1-5) and even worshiped. Lesser priests (1 Sam. 2:28) and priestly trainees wore less elaborate “ephods” made of linen whenever they appeared before the altar.
’Apuddah means “ephod; covering.” This word is a feminine form of 'êphôd (or 'ephod). The word occurs 3 times, first in Exod. 28:8: “And the curious girdle of the ephod, which is upon it, shall be of … gold, of blue, and purple, and scarlet, and fine twined linen.”