This cloud’s formal classification is Altocumulus stratiformis undulatus cavum. It’s quite a mouthful, and saying it out loud sounds a bit like casting a spell. But each of the terms just describes a specific element of the cloud. Let’s break it down into smaller pieces.

Alto comes from the Latin for ‘upper air’, and cumulus _means a ‘heap’ or ‘pile’. The combination of these two terms is used for solid clouds in the mid-level of the troposphere. _Stratiformis is a constructed Latin word meaning ’spread-out looking‘. _Undulatus _is Latin for ‘having waves’, while _cavum _means a ‘cavity’ or ‘hole’. Put them all together and you’ve described the cloud Linda Bruce (Member 20,743) spotted over Moray, Scotland: a clumpy cloud that’s quite high up, spread-out, and arranged into ripples, with a hole in it!

(The hole, in case you’re curious, was formed by an aircraft that climbed or descended through the cloud layer, causing its droplets to freeze and fall below.)