The usual Old English word for cloud was weolcan. In Middle English, skie also originally meant cloud. The four fundamental types of cloud classification (cirrus, cumulus, stratus, nimbus) were proposed by British amateur meteorologist Luke Howard (1772-1864) in 1802. Figuratively, as something that casts a shadow, from early 15c.; hence under a cloud (c.1500).
Thanks for the A2A. Okay, the most famous song in the world is no doubt 'Happy Birthday', followed by various Christmas carols (since the majority of human population is Christian indeed and since Santa is a really famous guy), folk songs, army marches and national anthems.
What is the world's longest Song title? Swedish group Rednex are the proud owners of the world's longest song title. In all there are 59 words and 344 characters but the capitalized words are just fragments of LISP code so we'll leave it up to you to decide which song takes home the record.