O.E. clud "mass of rock," from P.Gmc. *kludas, metaphoric extension 13c. based on similarity of cumulus clouds and rock masses. O.E. word for "cloud" was weolcan.
A visible body of very fine water droplets or ice particles suspended in the atmosphere at altitudes ranging up to several miles above sea level. Clouds are formed when air that contains water vapor cools below the dew point.
A distinguishable mass of particles or gas, such as the collection of gases and dust in a nebula.