altocumulus cloud

in atmospheric chemistry
A dappled layer of patch or cloud composed of flattened globules that may be arranged in groups, lines or waves collectively known as billows; 2000 - 6000 m; vertical velocities of 0.05 - 0.1 m s −1.
Source:
PAC, 1990, 62, 2167 (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2180