Emacs recognizes 5 modifier keys (arguably 6 depending on how you feel about Shift):
<Control> (C-), <Meta> (M-), <Super> (s-), <Hyper> (H-), and <Alt> (A-).
This capital A means that this key-sequence uses the uncommon <Alt> modifier. Since your Alt key, if you even have one, is most likely used for the <Meta> ...
Modifier key s- is called "Super". (event-modifiers 's-Y) returns (super), which says that s-Y uses (only) the super modifier.
See the Emacs manual, node Modifier Keys. What physical keyboard key, if any, might correspond to this logical modifier key depends on your system and hardware.
(event-convert-list '(super ?y)) returns 8388729, which is ...
(kbd "s-s") works just fine for me. Verified in both 27.1 and 26.3.
I suspect your window manager is capturing this sequence, and Emacs never sees it at all.
What does typing C-hks-s tell you?
If Emacs doesn't register the s-s, then I think you'll find that never actually reached Emacs, and you should start looking at your window manager's ...
Did you try just (kbd "s-s")? Does that not work? (I don't have a Super key, so I can't check.)
There should be no problem with the two s occurrences meaning different things. As a modifier, s- is realized by the Super key.
But it's a good question, considering that you can also define plain s as a prefix key, in which case, for example, you could ...
If you don't have a Meta key (it is often Alt) then you can use Escape, yes.
But in that case, what you want to use is Escape followed by Control + f, which we write as ESC C-f.
That is, Emacs writes the key sequence as ESC C-f when it talks to you about it.
A Meta key, which we write as M-, is a modifier key, which means you press and hold it down while you ...
Looks like it isn't defined.
Hyper is all on the OS's side - I don't think there's any way to map it natively, but you can stick in KC_MENU or something similar to be redefined in xmodmap or the equivalent for your distro.
http://www.usb.org/developers/hidpage/Hut1_12v2.pdf Page ~58. No
reference to hyper in ...
It's all about conventions, basically control is used for basic/normal editing commands (like C-k for kill-line) , and meta for extended commands (like M-k for kill-sentence).
There are also conventions for the core features, user space/modes, etc. which are explained (mostly) in the manual here, or blog posts like this one which is more easy to follow for ...
Here is one way to do it -- I'm using a generic example because I don't have any prior experience playing with the function jump-to-register:
(define-key global-map [?\s-s] (lambda () (interactive) (message "hello-world")))
Try this instead:
(global-set-key (kbd "s-C-i") 'move-line-up)
(global-set-key (kbd "s-C-k") 'move-line-down)
Dunno whether that works (I don't have a <super> key. The key description C-s means Control + s (character s, not super key).
Be aware, too, that C-i is the same as TAB.