From Glossary of Meteorology
(Or trade cumulus.) The characteristic cumulus cloud of the trade winds over the oceans in average, undisturbed weather conditions.
These clouds are generally 5000–7000 ft thick at peak development and are based at about 2000–2500 ft altitude. The individual cloud usually exhibits a blocklike appearance since its vertical growth ends abruptly in the lower stratum of the trade-wind inversion. A group of fully grown clouds show considerable uniformity in size and shape.