Why is a regular language called 'regular'?

Question

I have just completed the first chapter of the [*Introduction to the Theory of Computation*](http://www-math.mit.edu/~sipser/book.html) by *Michael Sipser* which explains the basics of finite automata. He defines a regular language as anything that can be described by a finite automata. But I could not find where he explains why a regular language is called "regular?" What is the origin of the term "regular" in this context?NOTE: I am a novice so please try to explain in simple terms!

Answer 1

It appears that the term "regular" was chosen by Stephen Kleene in the 1940s to describe "all representable (i.e., all regular) events" (page 8, https://www.maa.org/sites/default/files/images/upload_library/46/Pengelley_projects/Project-16/regLang-project.pdf, from https://www.maa.org/press/periodicals/convergence/regular-languages-and-finite-automata).

The term "regular" seems to be used to indicate that a language can be described with the operations of disjunction (or), product (concatenation), and iteration (*).