RE: C-x 2 and C-x 3

[Drew Adams]

j> So the most logical would be to name split functions by adding the
j> `SIDE' argument to the existing base function name using a template
j> "split-window-<SIDE>" thus creating new names (like Stefan 
j> already suggested):
j> split-window-below, split-window-above, split-window-right
j> split-window-left

Again:

d> if we really care about the selected window or which one
d> is new, then we probably should not speak anymore in terms
d> of the action as "splitting" a window but rather as "copying"
d> a window, to the right, below, or whatever:
d>
d> `copy-window-to-right', `copy-window-below'
d>
d> It's not just a `new-window-to-right' or `below'.  The new
d> window shows the same buffer.  It is essentially a window copy.

When you copy a file in Dired, you don't think in terms of "splitting" the file.
Yes, copying a window means that some other window will be smaller, and in that
sense "split" has some mileage.  But the confusion around "splitting" isn't
worth it, and "copy" lets you know that the new window is not just new, it's a
copy of the selected window (same buffer).

copy-window-below, copy-window-above,
copy-window-right, copy-window-left