nebula

nebula
[ˈnɛbjʊlə]
(pl. nebulae -liː 或nebulas)
  1. (Astronomy)a cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter
    (天文)星云
    ■(in general use) any indistinct bright area in the night sky, e.g. a distant galaxy
    (一般用语)雾影;星云状物
  2. (Medicine)a clouded spot on the cornea causing defective vision
    (医)角膜云翳
语源
  1. mid 17th cent. (as a medical term): from Latin, literally mist'
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