CUMULUS

Detached clouds, generally desnse with sharp outlines, developing vertically in the form of rising mounds, domes, or towers, of which the bulging upper part often resembles a cauliflower. The sunlit parts of these clouds are mostly brilliant white; their bases are dark and nearly horizontal.

Sometimes cumulus is ragged.

WMO (1957) International Cloud Atlas, as cited in H. R. Byers (1974) General Meteorology