@jlcrawf That would be an unusual definition. Merriam-Webster gives "a curve plotting performance against practice" or "the course of progress made in learning something." https://www.merriam-webster.com/dictionary/learning%20curve
@ProfWorr The whole notion of a "learning curve" is a metaphor at best. It's measurable for something like the size of a person's vocabulary, but it doesn't have a lot of meaning for a skill.