Why “rc”?

Today I was playing with some unix boxen[1].
Going back and forth between systems, I wrote many times /usr/local/etc/rc.d, /etc/rc3.d, /etc/rc.conf and so on. As time passed, I felt more and more the urge to know: why “rc“?

Well, the first search in google pointed to a page of the University of Indiana, which explained:

rc runcom (as in .cshrc or /etc/rc)

The rc command derives from the runcom facility from the MIT CTSS system, ca. 1965.
From Brian Kernighan and Dennis Ritchie, as told to Vicki Brown: “There was a facility that would execute a bunch of commands stored in a file; it was called runcom for “run commands”, and the file began to be called “a runcom”. rc in Unix is a fossil from that usage.”
Note: The name of the shell from the Plan 9 operating system is also rc.

As a later search revealed, the text had been taken from a much more authoritative source: THE unix FAQ, the collection of questions from comp.unix.questions and comp.unix.shell.
I find amusing that the Plan9 shell is called rc.

[1] before you correct me, from the jargon file:
boxen: /bok‚´sn/, pl.n.
[very common; by analogy with VAXen] Fanciful plural of box often encountered in the phrase ‘Unix boxen’, used to describe commodity Unix hardware. The connotation is that any two Unix boxen are interchangeable.