noun
General term for clouds in the sky; also used metaphorically for something cloud-like or unclear.
空に白い雲が浮かんでいる。
White clouds are floating in the sky.
雲が厚くなってきたから、雨が降るかもしれない。
The clouds are getting thicker, so it might rain.
曇り refers to cloudy weather or a cloudy state, while 雲 is the physical cloud itself.
霞 is a haze or mist, often thinner and more atmospheric than 雲, which is a distinct cloud.
The kanji 雲 is a pictograph of a cloud. The reading くも is native Japanese, with uncertain deeper origin.