macula

noun

1. An oval yellow spot near the center of the retina of the human eye, histologically defined as having two or more layers of ganglion cells, responsible for detailed central vision.
2. A small chamber of the inner ear of certain vertebrates filled with endolymph and containing an otolith.
3. A spot, as on the skin, or on the surface of the sun or of some other luminous orb.
4. A rather large spot or blotch of color.
5. In planetary geology, an unusually dark area on the surface of a planet or moon.