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This is the Bible's word for the thick, dark cloud, the heavy mass of cloud that piles up in the sky and lets down rain. It is a more specific word than the ordinary term for a cloud: where that general word can name any cloud (including the bright pillar that led Israel), this one leans toward the dark, water-laden storm cloud, the kind that gathers, thickens, and bursts.

Because of that, its natural home is weather. Clouds here rise from the sea before a downpour, blacken the sky, are loaded with moisture, pour out water, and are ordered to withhold rain in judgment. Even where the word is used for a picture (favor that comes like a rain cloud, sins that are wiped away like a cloud, a life that passes as swiftly as a cloud), the image behind it is still this heavy cloud of the sky.

The same dark storm cloud is also how the poets saw God arrive. When the Lord comes down in power he comes veiled in thick cloud, makes the clouds his chariot, and rides on a swift cloud. So the one word covers both the ordinary weather overhead and the storm in which God shows his presence and majesty.

In one verse the same word names a thicket, a stand of dense brush that people flee into to hide. The link to the usual meaning is the shared idea of a thick, packed mass: as clouds are a dense mass of vapor, a thicket is a dense mass of growth.

This reading rests on a single occurrence, Jeremiah 4:29, where the terrified townspeople run for cover into the brush and up among the rocks. The meaning is not certain: because the word almost everywhere means cloud, a few would keep that sense here too, but the picture of people scrambling into hiding fits dense scrub far better, and the standard lexicons list a thicket here.