Cloud1, n.
n. [Most probably from A-S. clad, which corresponds in its form to the English word, though it signifies a rock or hillock; but clouds frequently resemble rocks or hillocks in the sky or air.]
Sense 1. A collection of visible vapor, or watery particles, suspended in the atmosphere.
I do set my bow in the cloud, and it shall be for a token of a covenant between me and the earth. Gen. ix. 13.
As when from mountain tops the dusky clouds Ascending, while the north wind sleeps, o'erspread Heaven's cheerful face. Milton.
Sense 2. A mass or volume of smoke, or flying dust, resembling vapor. “A cloud of incense.” Ezek. viii. 11.
Sense 3. A dark vein or spot on a lighter material, as in marble.
Sense 4. That which has a dark, lowering, or threatening aspect; obscurity; darkness; danger; as, a cloud of sorrow; a cloud of war; a cloud upon the intellect.
Sense 5. A great crowd or multitude. “So great a cloud of witnesses.” Heb. xii. 1.
A classification of clouds according to their chief forms was first proposed by the meteorologist Howard, and this is still substantially employed. The following varieties and sub-varieties are recognized: (a.) CIRRUS. This is the most elevated of all the forms of clouds; is thin, long-drawn, sometimes looking like carded wool or hair, sometimes like a brush or broom, sometimes in curl-like or fleece-like patches. It is the cat's tail of the sailor. (b.) CUMULUS. This form is somewhat elevated, and appears in large masses of a hemispherical form, or nearly so, above, but flat below, one often piled above another, forming great clouds, common in the summer, and presenting the appearance of gigantic mountains crowned with snow. It often affords rain and thunder-gusts. (c.) STRATUS. This form is moderately high, and appears in layers or bands extending horizontally. (d.) NIMBUS. This form is moderately high, and is characterized by its uniform gray tint and ragged edges: it covers the sky in seasons of continued rain, as in easterly storms, and is the proper rain-cloud. The name is sometimes used respecting a raining cumulus, or cumulo-stratus. (e.) CIRRO-CUMULUS. Very high, and consisting, like the cirrus, of thin, broken, fleece-like cloud, but the parts are more or less rounded and regularly grouped. It is popularly called mackerel sky. (f.) CIRRO-STRATUS. High, and having the patches of cirrus coalescing into long strata; between cirrus and stratus. (g.) CUMULO-STRATUS. A form between cumulus and stratus, often assuming at the horizon a black or bluish tint. — Fog is a cloud, motionless, or nearly so, lying near or in contact with the earth's surface; and storm-cloud is cloud lying quite low, without form, and driven rapidly with the wind.