lemon āļāļ·āļāļāļ°āđāļĢ lemon āļāļ·āļāļāļ°āđāļĢ A spiny, Asian evergreen tree (Citrus limon) widely cultivated for its yellow, egg-shaped fruit.The fruit of this tree, having a yellow aromatic rind and juicy, acid pulp.Lemon yellow. Informal One that is unsatisfactory or defective: Their new car turned out to be a lemon. Lemon-yellow.Made from lemons.Tasting or smelling like lemons.