The symbol for the element potassium is "K." This symbol derives from the Latin word "kalium," which refers to potash, a source of potassium. In the periodic table, potassium is classified as an alkali metal and has the atomic number 19. It is essential for numerous biological functions in both plants and animals, including nerve signal transmission and muscle contraction. Potassium naturally occurs in many foods, particularly fruits and vegetables like bananas, oranges, and potatoes. Maintaining a proper balance of potassium in the body is important for overall health, influencing fluid balance, heart function, and blood pressure regulation.