One of the correct, but subtle analogies with Ruby is that in times prior to 1.8.x there was nothing, but reference implementation. For the question "define what is Ruby?" the answer was "this MRI".
The differences between, say, Scheme and CL are few and subtle - #' and funcall syntax, behavior of nil, etc. all the foundational special forms and general function application rule are the same.
Of course, CL is a much bigger language, but all its features never broke the basis on which everything is founded - a few special forms, list structure, general evaluation rule with exceptions only for these special forms, each of which follow its own rules.
Most of CL's features are macros and libraries, so they do enrich the base language, without breaking it up.
The differences between, say, Scheme and CL are few and subtle - #' and funcall syntax, behavior of nil, etc. all the foundational special forms and general function application rule are the same.
Of course, CL is a much bigger language, but all its features never broke the basis on which everything is founded - a few special forms, list structure, general evaluation rule with exceptions only for these special forms, each of which follow its own rules.
Most of CL's features are macros and libraries, so they do enrich the base language, without breaking it up.