A foeder (pronounced FOOD-er; sometimes spelled foedre) is essentially a wooden barrel set on end used for either long term fermentation or primary fermentation and innoculations. A foeder can range in size from home brewer to commercial scale.
Casey Brewing and Blending wine barrels converted to foeders
Smaller sized Foeder example in a brewery located in Dusetos, Lithuania
Bearded Iris Brewing 1000G foeders
Bearded Iris Brewing small foeder for experimental brews for primary fermentation and inoculation.