Cloud
Old English clūd ‘mass of rock or earth’; probably related to clot. cloud (sense 1 of the noun) dates from Middle English.
wiktionary
From Middle English cloud, cloude, clod, clud, clude, from Old English clūd(“mass of stone, rock, boulder, hill”), from Proto-Germanic *klūtaz, *klutaz(“lump, mass, conglomeration”), from Proto-Indo-European *gel-(“to ball up, clench”).
Cognate with Scots clood, clud(“cloud”), Dutch kluit(“lump, mass, clod”), German Low German Kluut, Kluute(“lump, mass, ball”), German Kloß(“lump, ball, dumpling”), Danish klode(“sphere, orb, planet”), Swedish klot(“sphere, orb, ball, globe”), Icelandic klót(“knob on a sword's hilt”). Related to English clod, clot, clump, club. Largely displaced native Middle English wolken, wolkne from Old English wolcen (whence Modern English welkin), the commonest Germanic word (compare Dutch wolk, German Wolke).
etymonline
cloud (n.)
Old English clud "mass of rock, hill," related to clod.
The modern sense "rain-cloud, mass of evaporated water visible and suspended in the sky" is a metaphoric extension that begins to appear c. 1300 in southern texts, based on similarity of cumulus clouds and rock masses. The usual Old English word for "cloud" was weolcan (see welkin). In Middle English, skie also originally meant "cloud." The last entry for cloud in the original rock mass sense in Middle English Compendium is from c. 1475.
The four fundamental types of cloud classification (cirrus, cumulus, stratus, nimbus) were proposed by British amateur meteorologist Luke Howard (1772-1864) in 1802.
Meaning "cloud-like mass of smoke or dust" is from late 14c. Figuratively, as something that obscures, darkens, threatens, or casts a shadow, from c. 1300; 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.
cloud (v.)
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.
