Cumulus

urn:aero:airm:1.0.0:ConceptualModel:Subjects:Meteorology:Cumulus

Detached cloud, generally dense and with sharp outlines, developing vertically in the form of rising mounds, domes or towers, of which the bulging upper part is often like a cauliflower. The sunlit parts are mostly brilliant white and the base is relatively dark and nearly horizontal. Sometimes Cumulus clouds are ragged.

Source: WMO International Meteorological Vocabulary,