The high priest's embroidered vest, a plain linen garment anyone serving at worship might wear — and, apparently, an object you could consult.
The word covers more than one thing. The high priest's ephod is a richly worked garment of gold, blue, purple and scarlet, with two onyx stones on the shoulders carrying the names of the tribes and the breastpiece fastened to its front. A plain linen ephod is also worn by others: the boy Samuel has one, and David wears one to dance before the ark. But an ephod is also something you bring and consult. David calls for it twice when he needs to know what to do, and Gideon makes one from captured gold that becomes an object of worship and a snare to his family. Whether that ephod is a garment, a garment draped over an image, or something else entirely is not said.
Disputed. The priestly garment is described in detail. The ephod David consults and the ones Gideon and Micah make are not, and scholars disagree about whether they are the same garment used for inquiry, or a different object that shares the name.