A Yankee auction is a single-attribute multiunit auction running like a Dutch auction, where the bids are the portions of a total amount of identical units. The total amount of auctioned items is firm in a Yankee auction unlike a Brazilian auction.
A Yankee auction is a type of auction where you bid on parts of a whole, similar to a Dutch auction.  The total number of items up for sale is set, and the bidding process works like a Dutch auction. Unlike a Brazilian auction, the total amount of items being sold is fixed.