Product size refers to the physical dimensions of an item, which can include its height, width, depth, and weight. Understanding product size is essential for consumers to ensure that the item fits their needs, whether it's for storage, usage, or transportation. In retail, product size can influence purchasing decisions, as customers often compare sizes to find the best fit for their space or lifestyle. For example, when shopping for furniture, knowing the size of a sofa helps buyers determine if it will fit in their living room.