nebula
- 01 B2 Upper Intermediate
a huge cloud of gas and dust in space, which can look like a bright or dark patch in the sky.
an interstellar cloud of dust, hydrogen, helium and other ionized gases.
Simple“The Orion Nebula is one of the brightest objects you can see in the night sky.”
In context“Astronomers used the infrared telescope to peer through the thick dust of the nebula, revealing the birth of several new stars within its core.”
UsageThe plural form can be either 'nebulas' or 'nebulae'.
Synonymsinterstellar cloud - 02 C2 Proficiency
a faint, cloudy spot on the clear front part of the eye.
a slight opacity or white spot on the cornea, typically resulting from injury or infection.
Simple“The old medical book described a nebula that partially blocked the patient's vision.”
In context“The physician noted a faint nebula on the left cornea, though it appeared to be a stable scar rather than an active infection.”
Teacher's tipThis sense is rarely encountered outside of historical medical texts; modern practitioners use more specific clinical terms for corneal scarring.
Synonymsopacitycloudiness
“Orion KL is a smaller part of the Great Orion Nebula, which can be seen, even without a telescope, as a reddish blob below the belt of the Orion constellation.”
Borrowed from Latin nebula (“little cloud, mist”). Akin to Ancient Greek νεφέλη (nephélē, “cloud”), German Nebel (“mist, nebula”), Old Norse nifl, Polish niebo (“sky, heaven”), Russian не́бо (nébo, “sky”).
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.