Word Origin & History
cloud
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. Cloudy is O.E. cludig (in the rock sense), in the water vapor sense, c.1300. Cloudburst (1817, Amer.Eng.) parallels Ger. Wolkenbruch. The imaginary city Cloud Cuckoo Land, built in air, is from Aristophanes' Nephelokokkygia in "The Birds" (414 B.C.E.). Cloud nine is 1950s, Amer.Eng., of uncertain origin or significance. There was a similar association of cloud seven, but some connect the phrase with the 1896 International Cloud-Atlas, long the basic source for cloud shapes, in which, of the ten cloud types, cloud No. 9, cumulonimbus, was the biggest, puffiest, most comfortable-looking.