Cloud A hydrometeor consisting of a visible aggregate of minute particles of liquid water or ice, or both, suspended in the free air and usually not touching the Earth's surface. It may also include larger particles of liquid water or ice (precipitation particles) and non-aqueous liquid or solid particles such as those present in fumes, smoke and dust (aerosols). Cloudiness is the same as cloud cover; but usually it is used in a very general sense. Cloud