The medicine I am giving you may taste bitter,
but a result should be some much better
technical writing. So far, 'multi-screen' is
just jargon of an in-group, really 'in' because
it wasn't clear to me, and my background in
computing is plenty deep.

You still just don't 'get it': E.g., that 'mobile', smartphones, wrist watches, glasses, or tablets
are the main issue just was not at all clear to
an 'outsider.

"Multi-screen', no matter how common and comfortable you and your colleagues are with the term, just is not, Not, NOT clear. Here is an example: Do you mean a workstation with four screens? Is that what you are talking about, that is, software from one Web site that makes separate use of each of the four screens? How the heck to know?

Or maybe you meant essentially multiple windows, treated separately, from one Web site on one physical screen? How the heck to know?

Or, essentially every Web site now is 'multi-screen' in that it works if the resolution on a screen is 640 x 480, ..., 3000 x 4096 and lots of other screen resolutions and physical screen sizes. Also each Web site is 'multi-screen' in the sense that 500 people, each in a different location, can be viewing Web pages from the site all at the same time, that is, the site is serving 500 screens.

Instead, apparently by 'multi-screen' you mean the different screens 'types' on end user devices from workstations, desktops, laptops, and tablets down to
smart phones and maybe wrist watches and glasses. But
if each of these devices has a standard Web browser, then
what is the significant difference? Maybe the difference is
swipes versus clicks or some such, in which case 'screen' is
not really the point.

The issue is being clear when using words with meanings
that are not in a standard dictionary. Such a word is a
'term' and, thus, needs at least a definition and likely
also motivation, explanation, and examples. Else are
on the way to jargon and gibberish.

Such bad writing is endemic in practical computing and a big, huge, problem for the field. Even computer science
very much needs to 'up its game' to catch up with physics and especially mathematics.

Apparently my little lesson in good technical writing 101
rubbed some feathers the wrong way, but the lesson stands --
good definitions are crucial, and 'multi-screen' screams out for a good definition.

It still is not clear, without a lot of guessing, just
what is the significance of any definition of 'multi-screen' for building a Web site. That is, the Web site
mostly shouldn't care. E.g., I'm building a Web site, and the pages look fine, and there is no logic at all in either the server or what is sent to the client on what the heck the screen size is. My solution: Each Web page is exactly 800 pixels wide. Period. If the actual window used on the client device is less than 800 pixels wide, then the client
device is welcome to add horizontal scroll bars. For JavaScript, I have tried hard not to write any and so far
have been successful although some of Microsoft's software
writes some JavaScript for me. So, in particular, for my Web site, I still can't find a meaning of 'multi-screen' that is useful.

I'm talking about good definitions and clear communications.