What does "sadden" mean?

Sadden: To make sad. Specifically: (a) To render heavy or cohesive. [Obs.] Marl is binding, and saddening of land is the great prejudice it doth to clay lands. Mortimer. (b) To make dull- or sad-colored, as cloth. (c) To make grave or serious; to make melancholy or sorrowful. Her gloomy presence saddens all the scene. Pope.