A cloud shape added to a technical drawing to highlight a region that has been modified since the previous version of the drawing.

Having one's head in the clouds: prone to daydreaming, or thinking impractically.

(meteorology) The percentage or fraction of the sky obscured by clouds.

(physics) A mathematically defined region around an atomic nucleus defined by a high probability that the atom's electrons will be present in that region.

The act of firing munitions containing silver iodide at passing clouds to make them more likely to produce rain.

(Internet) tag cloud

Alternative spelling of cloud seeding

polar stratospheric cloud

(meteorology) A cellular pattern of pouches hanging underneath the base of a cloud.

plural of cloud base