The symbol for potassium is "K," derived from its Latin name "kalium." Potassium is a chemical element with the atomic number 19 and is classified as an alkali metal. It is essential for various biological processes in living organisms, including nerve function, muscle contraction, and maintaining fluid balance. Potassium is also a critical nutrient found in various foods, particularly fruits and vegetables such as bananas, oranges, potatoes, and leafy greens. In addition to its biological importance, potassium is used in various industrial applications, including fertilizers, glass production, and as a salt substitute in low-sodium diets.