Short, thickened, mostly underground stem that constitutes the resting stage of certain seed plants.
It is often an organ of food storage, reproduction, or both. It bears minute scale leaves, each with a bud that has the potential for developing into a new plant. The common potato is a typical tuber; the much-reduced leaves and associated buds form its "eyes." The term is also used imprecisely but widely for fleshy roots or dahlia , actually a tuberous root).