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Old English clud "mass of rock, hill," related to clod. Metaphoric extension to "raincloud, mass of evaporated water in the sky" is attested by c.1200 based on similarity of cumulus clouds and rock masses. The usual Old English word for "cloud" was weolcan. In Middle English, skie also originally meant "cloud."
The four fundamental types of cloud classification (cirrus, cumulus, stratus, nimbus) were proposed by British amateur meteorologist Luke Howard (1772-1864) in 1802. Figuratively, as something that casts a shadow, from early 15c.; hence under a cloud (c.1500). In the clouds "removed from earthly things; obscure, fanciful, unreal" is from 1640s. Cloud-compeller translates (poetically) Greek nephelegereta, a Homeric epithet of Zeus.
early 15c., "overspread with clouds, cover, darken," from cloud (n.). From 1510s as "to render dim or obscure;" 1590s as "to overspread with gloom." Intransitive sense of "become cloudy" is from 1560s. Related: Clouded; clouding.
The Hebrew so rendered means "a covering," because clouds cover the sky. The word is used as a symbol of the Divine presence, as indicating the splendour of that glory which it conceals (Ex. 16:10; 33:9; Num. 11:25; 12:5; Job 22:14; Ps. 18:11). A "cloud without rain" is a proverbial saying, denoting a man who does not keep his promise (Prov. 16:15; Isa. 18:4; 25:5; Jude 1:12). A cloud is the figure of that which is transitory (Job 30:15; Hos. 6:4). A bright cloud is the symbolical seat of the Divine presence (Ex.29:42, 43; 1 Kings 8:10; 2 Chr. 5:14; Ezek. 43:4), and was called the Shechinah (q.v.). Jehovah came down upon Sinai in a cloud (Ex. 19:9); and the cloud filled the court around the tabernacle in the wilderness so that Moses could not enter it (Ex. 40:34, 35). At the dedication of the temple also the cloud "filled the house of the Lord" (1 Kings 8:10). Thus in like manner when Christ comes the second time he is described as coming "in the clouds" (Matt. 17:5; 24:30; Acts 1:9, 11). False teachers are likened unto clouds carried about with a tempest (2 Pet. 2:17). The infirmities of old age, which come one after another, are compared by Solomon to "clouds returning after the rain" (Eccl. 12:2). The blotting out of sins is like the sudden disappearance of threatening clouds from the sky (Isa. 44:22). Cloud, the pillar of, was the glory-cloud which indicated God's presence leading the ransomed people through the wilderness (Ex. 13:22; 33:9, 10). This pillar preceded the people as they marched, resting on the ark (Ex. 13:21; 40:36). By night it became a pillar of fire (Num. 9:17-23).