The Wikipedia article is a okayish description
https://en.wikipedia.org/wiki/Creative_coding . I guess if I had to describe it as short as possible I would say: using code to create art. Some good examples are the works of Anders Hoff
https://inconvergent.net/generative/ or lots of projects on
https://www.creativeapplications.net/ and of course the pioneering works of Frieder Nake et al. Am examples for generative design would be the old logo of the MIT Media lab
https://www.engadget.com/2011-03-10-mit-media-lab-gets-a-mul...