HCI = Human Computer Interaction[1] for the curious. This is the name for the older research discipline that UX (user experience) grew out of. I'm familiar with the term from reading "An Introduction to Human Factors Engineering" (2004) by Wickens, et al. But wikipedia dates it's first use to a paper by James Carlisle in 1976.

[1] https://en.wikipedia.org/wiki/Human–computer_interaction

Edit: to add further context.

Thank you, that's a very interesting topic. I watched lots of videos and material about computer interfaces of the early days to present.

It feels a bit like the magic and larger innovations stopped at some point in the 80/90's. It's rare to find new UI experiments.

The following keeps me hoping: https://www.youtube.com/watch?v=YGVCVqlXg0Y unfortunately it's just an animated concept.

Did you miss the iphone and gesture based capacitive touch interfaces?

Pen plus touch on the surface devices is also crazy better than keyboard/mouse for plenty of things