(astronomy) A cloud in outer space consisting of gas or dust (e.g. a cloud formed after a star explodes). / (archaic, medicine) A white spot or slight opacity of the cornea.

plural of nebula

plural of nebula

(astronomy) A diffuse nebula visible in the night sky below Orion's Belt; it is approximately 40 light years across. It is one of the brightest nebulae visible to the naked eye and is the closest region of stellar formation to Earth.

(astronomy) A type of nebula that does not emit or reflect (visible) light, and thus obscures light sources behind it.

(astronomy) A nebulosity surrounding a dying red giant, consisting of material expelled by the star.

(astronomy) A nebula that consists of dust which reflects starlight and appears blue in photographs.

(astronomy) A stage in stellar evolution when a star starts to shed its outer layers before coming a true planetary nebula.

(astronomy) A stage in stellar evolution when a star starts to shed its outer layers before coming a true planetary nebula.

plural of planetary nebula