I've heard that General Magic [1] were the originator of the phrase "Cloud" (compute & data distributed across heterogeneous hardware).
I went digging and found an earlier WIRED article on General Magic, using the word a few times [2].
Sun's motto was "The network is the computer" actually.
And back in the 2000s, CERN was having a go at their own cloud infrastructure, with the name of Grid Computing.
Cloud computing was a term at least as far back as 1999. We didn't have the technology quite right that soon, but we had the idea and the term:
https://en.wikipedia.org/wiki/Opsware
https://www.wired.com/2000/08/loudcloud/
Archived version of Wired article: https://archive.ph/TeLPQ