In Chapter 3 of D&E, Stroustrup wrote:
I picked C++ because it was short, had nice interpretations, and wasn’t of the form “adjective C.”
++can, depending on context, be read as “next,” “successor,” or “increment,” though it is always pronounced “plus plus.” The name C++ and its runner up ++C are fertile sources for jokes and puns – almost all of which were known and appreciated before the name was chosen. The name C++ was suggested by Rick Mascitti. It was first used in December of 1983 when it was edited into the final copies of [Stroustrup,1984] and [Stroustrup,1984c].
In chapter 1 of TC++PL, Stroustrup wrote:
The name C++ (pronounced “see plus plus”) was coined by Rick Mascitti in the summer of 1983. The name signifies the evolutionary nature of the changes from C; “
++” is the C increment operator. The slightly shorter name “C+” is a syntax error; it has also been used as the name of an unrelated language. Connoisseurs of C semantics find C++ inferior to ++C. The language is not called D, because it is an extension of C, and it does not attempt to remedy problems by removing features. For yet another interpretation of the name C++, see the appendix of [Orwell,1949].
The “C” in C++ has a long history. Naturally, it is the name of the language Dennis Ritchie designed. C’s immediate ancestor was an interpreted descendant of BCPL called B designed by Ken Thompson. BCPL was designed and implemented by Martin Richards from Cambridge University while visiting MIT in the other Cambridge. BCPL in turn was Basic CPL, where CPL is the name of a rather large (for its time) and elegant programming language developed jointly by the universities of Cambridge and London. Before the London people joined the project “C” stood for Cambridge. Later, “C” officially stood for Combined. Unofficially, “C” stood for Christopher because Christopher Strachey was the main power behind CPL.