photo #4334873

When describing a cloud like this Altocumulus, we might add the term perlucidus to indicate that there are gaps between the cloud’s elements, or cloudlets, through which the sky above is visible. Think of the view out a window visible between the gaps in a lowered blind. As you can see in this Altocumulus perlucidus sunrise spotted over Plaquemine, Louisiana, US by Larry Smith (Cloud Appreciation Society Member 57,002), the gaps between the cloudlets are obvious directly above, but not when viewing it side-on, towards the horizon.