This exact topic came up in another thread a.few months ago, and I did some digging: I believe the term "compute node" was first used in the context of the Int

This exact topic came up in another thread a.few months ago, and I did some digging: I believe the term "compute node" was first used in the context of the Intel ASCI Red supercomputer that was installed at Sandia in 1997. This later led to the Cray XT3, XT4, XT5 families of machines that used the same terminology. But I believe the term was not in generic usage outside of those specific supercomputers until around 2005-2010. And it is more recently that the term has been extended beyond referring to hardware.