The word "苋菜" is formed by combining the character "苋", which specifically refers to the amaranth plant and incorporates a grass radical (艹) for its plant category along with a phonetic component, with the character "菜", meaning vegetable, which also uses a grass radical to denote its plant-based nature. This results in a compound term where "苋" identifies the particular plant and "菜" clarifies its role as an edible vegetable.