To assign to a bidder at an auction by a knock or blow of the hammer. Property is said to be “knocked down” when the auctioneer, by the fall of his hammer, or by any other audible or visible announcement, signifies to the bidder that he is entitled to the property on paying the amount of his bid, according to tbe terms of the sale. “Knocked down” and “struck off” are synonymous terms. Sherwood v. Reade, 7 Hill (N. Y.) 430.