Stack \Stack\, v. t. [imp. & p. p. {Stacked}; p. pr. & vb. n. {Stacking}.] [Cf. Sw. stacka, Dan. stakke. See {Stack}, n.] To lay in a conical or other pile; to make into a large pile; as, to stack hay, cornstalks, or grain; to stack or place wood. {To stack arms} (Mil.), to set up a number of muskets or rifles together, with the bayonets crossing one another, and forming a sort of conical pile.