Cloud (n.) - From metaphor to metaphor.
A visible mass of particles usually floating some distance above the ground.
Recently it’s come to refer to offsite resources accessed via the internet.
History & Etymology
If you’re looking for the origin of the word cloud all you need to do is look down. That’s right the words cloud evolved from meant rock. Clod meant “a mass of rock, or hill”
The first time the word cloud appears, even in a metaphorical sense, to refer to clouds was in the 1300 hundreds. Even in the passage quoted by the OED the word cloud is appended with “of the air” to differentiate it from the original use of cloud.
a1340 R. Rolle Psalter xvii. 13 Clowdes of þe aeire.
Even in modern English we still use a variant of the word cloud to refer to dirt. Clod, a dirt clod, I don’t think I’ve heard this word since I was a child so I’m not sure if it’s still in use but I suspect it is. Even a version of this word came in to use in a medical since, clot. Like a blood clot, or any coagulation of liquid could be called a clot.
This word that was originally used metaphorically is now being used as another metaphor. As early as 1977 ARPANET and CSNET were using the symbol of a cloud in diagrams to represent entire systems or networks who’s inner-workings weren’t required to be understood to understand the rest of the diagram.
But the first recorded time the word cloud to refer to computer systems was in 1996 in internal Compaq documents, and it was popularized by Amazon in 2006 when they released their first cloud computing product.