Of course,
Scheme *is* Lisp rather than just part of the family. 
 I don't really think that's fair.  Scheme is a bit closer to the lambda
 calculus and many - most? - Lisps in some respects, perhaps, but
 identifying Lisp with the lambda calculus is ignoring the difference
 between theory and implementation.
 I consider Scheme one member of the Lisp family, but no more than that.
 ...
  One of the instructors [in a video], who was one
of the creators of
 Scheme and so should know better than me, mentions in passing near
 the beginning that the particular Lisp used in the course is known as
 Scheme but only uses Lisp to refer to it from then on. 
 That hardly means much.  An introductory course, especially one which
 focuses on the theoretical aspects, or the common aspects, is likely to
 do exactly that without any implication that it's fair to identify the
 whole language family with any particular implementation.  If I were to
 teach a course on C, for example, I might well mention that the
 compiler I'm using is whichever one it is, but then proceed to teach C,
 rather than any particular implementation of C. 
 
C is standardised, so it's straightforward to teach standard C. But you
can't teach "standard Lisp" without picking a standard: CL or Scheme
(and then which Scheme standard?)
What's amusing is that the didactic books (HTDP and so on) frequently
teach *non-standard* Scheme. (Go figure... :| )
--Toby
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