bug#3035: 23.0.92; doc, terminology for graphics, display, terminal, etc.

This is mainly about the Elisp manual, but some of it might also apply
to the Emacs manual.
 
1. `display-graphic-p' has apparently been with us since Emacs 22, but
there is still no mention of it in the Elisp manual. Please document
how/when it is to be used, compared, for instance with when to use
`window-system'.
 
2. In the Elisp manual, I see the use of terms such as "graphical
terminal", "graphicical display" (also "graphics display"),
"(non-)graphics-capable display", "text terminals" (opposed to
graphical), "graphic characters", and "graphical attributes", without
any real explanation or definition. (BTW, shouldn't that always be
"graphic", not "graphical"?)
 
Does "graphic" imply mouse support? font support? fringe support?
color support? menu support? tool-bar support, image support?
multiple-frame support? All of these? Does non-graphics imply absence
of all or limited support of some (e.g. frames and colors and fonts)?
 
And there are apparently finer distinctions (which also don't seem to
be explained), such as "graphical terminal that supports extended
ASCII input" (unless what is really meant is "graphical terminal,
which supports extended ASCII input"). And "graphic display capable of
displaying several frames and several different fonts" (unless what is
really meant is that all graphic displays are so capable).
 
And "graphical menu bar" (is there a non-graphical one?), "graphical
environment"... And there are undefined terms, such as
"multi-monitor", that are quoted (they should not be). Quoting a term
is not a substitute for explaining or defining it. (BTW, there is
quite a bit of such inappropriate quoting in the manuals -
e.g. "function keys".)
 
Perhaps it would be good to see all of these terms explained together
somewhere: display, terminal, monitor, screen, graphic *, frame. (I
assume none of these are synonyms.) Node Multiple Displays is a start,
but it doesn't bring it all together (as it shouldn't, since it is
only about multiple displays). And then please add xrefs back to that
section in places where the various terms are used.
 
Perhaps if I reread the whole manual front to back it would become
clear, but this is a muddle for me, so far.
 
My ignorance and confusion are no doubt due partly to the fact that I
haven't used Emacs without graphics support for 20 years, and if I did
perhaps I'd dig in an find out what gives. But I suspect that this
could be better presented for everyone.
 
Thanks.
 
 
 

In GNU Emacs 23.0.92.1 (i386-mingw-nt5.1.2600)
 of 2009-03-30 on SOFT-MJASON
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4)'