C-x 2 and C-x 3

[Chong Yidong]

Martin recently introduced the command names

  split-window-above-each-other -> C-x 2
  split-window-side-by-side     -> C-x 3

for which split-window-{vertically|horizontally} are now aliases.

I don't mind the attempt to address the vertical/horizontal ambiguity,
but the new names aren't ungrammatical.  In English, "split X above each
other" sounds like a nonsense phrase, and "split X side by side" isn't
much better.

How about split-window-by-width or split-window-by-height?  Or can
someone suggest something better?