Stack/stæk/ Definition 1 of 5Pro Tip 1/3Visual Imagery Use 'stack' when you can visualize a neatly ordered pile, often square or rectangular in shape. A stack of towels was neatly arranged on the shelf. Pro Tip 2/3Neat Arrangement 'Stack' implies careful placement, not just a random pile. His room was tidy, with a stack of magazines on the table. Pro Tip 3/3Vertical Alignment Items in a 'stack' are usually aligned vertically, one on top of the other. She admired the stack of coins she'd saved.