galgal

This is a wheel named for what it does. The word doubles a short root meaning "to roll," so the sound of it already carries the idea of something turning over and over. The plainer word for a wheel (אוֹפָן) simply names the object, with its rim and spokes; this one tends to turn up where wheels are moving and making noise.

That is why most of its appearances belong to scenes of speed and dread. An advancing army's wheels are like a storm wind, an invader's wheels rumble until fathers do not turn back for their children, and lists of enemy equipment set wheels beside chariots as the gates of a city give way.

Two uses stand apart. In Ecclesiastes it is the wheel above a well, the pulley the rope runs over to draw water up, and its breaking is one of the pictures for a life running down. In Ezekiel's vision of God's throne it names the whirling wheels underneath the winged creatures, and in one verse it is called out over those wheels as though they were being addressed by name.

The same rolling picture moves from wheels to whatever the wind sends tumbling. In dry country a dead, ball-shaped plant snaps off at the root at the end of summer and rolls across open ground for miles, and light chaff and dust lift and spin the same way. That is the image here: not a wheel, but something rolling helplessly wherever the wind takes it.

Both times the word is used this way it belongs to a threat against nations. One psalm asks God to make Israel's enemies like the tumbling stuff before the wind, and Isaiah says the roaring peoples will be chased like it before a gale. The point of the picture is not only speed but weightlessness: what looked massive turns out to have no root and nothing to hold it down. It sits beside chaff (מוֹץ) in exactly these lines.

Once, in a storm scene where thunder answers, the word seems to name the whirling wind itself rather than what the wind carries. Readers have gone both ways on that verse, and either way the scene is full of things spinning in a gale.