bash (or rather readline which is the line editing library used by bash) like most other shells since the early 80s has two line editing modes: emacs or vi, based on those two popular text editors.
Bash being the GNU shell and GNU emacs being one of GNU's star applications, the default mode there is emacs. You can switch between both with set -o emacs and set -o vi (also bindkey -e/bindkey -v in tcsh or zsh). Ksh also has set -o gmacs for Gosling emacs which is the one set as default on Solaris for instance.
So it's more about the different of meaning of the yank word in emacs vs vi.
Both emacs and vi were written in the late 70s long before either bash (1989) or vim (1991).
If you look at the vi doc from 2BSD from 1979:
The operator y yanks a copy of the object which follows
into the unnamed buffer. If preceded by a buffer name, "xy,
where x here is replaced by a letter a−z, it places the text
in the named buffer. The text can then be put back in the
file with the commands p and P; p puts the text after or be‐
low the cursor, while P puts the text before or above the
cursor.
Emacs doesn't have paste buffers, it has one killring that records text that has been killed or copied into it. The yanking is seen as being in the other direction, pulled from that killring as opposed to pulled from the text into the kill ring.
In GNU emacs doc from around 1985, we find:
Yanking is getting back text which was killed. The usual way to
move or copy text is to kill it and then yank it one or more times.
You'd see that bash has widgets from both editors that can bind to keys or key combinations:
$ bash -c 'bind -l' | grep -i yank
vi-yank-arg
vi-yank-pop
vi-yank-to
yank
yank-last-arg
yank-nth-arg
yank-pop
(the vi ones being mostly undocumented).
Default bindings:
$ bash -o vi -c 'bind -pm vi' | grep yank
"_": vi-yank-arg
# vi-yank-pop (not bound)
"Y": vi-yank-to
"y": vi-yank-to
"\C-y": yank
# yank-last-arg (not bound)
# yank-nth-arg (not bound)
# yank-pop (not bound)
$ bash -o vi -c 'bind -pm vi-insert' | grep yank
# vi-yank-arg (not bound)
# vi-yank-pop (not bound)
# vi-yank-to (not bound)
"\C-y": yank
# yank-last-arg (not bound)
# yank-nth-arg (not bound)
# yank-pop (not bound)
See how you still get a emacs-style Ctrl+y in vi insert mode; the undocumented vi-yank-arg bound on _ also uses emacs-style terminology and behaves similarly to the yank-last-arg emacs widget. I have no idea what vi-yank-pop is meant to do. The NEWS file from the bash source distribution says it's a vi-mode version of emacs-mode yank-pop, though that doesn't make sense since vi has no kill-ring.
