I'm not sure if anybody said it yet, but I think a simple figure embracing something would be pretty universal for a "save" and then delete would be that figure rejecting something by putting his hands up and turning its head.

Down arrow pointing to a horizontal line.

Seems pretty easy...

You need an icon of a paper with text on it, an arrow pointing from the paper down to a larger box.

If the share icon is a box with an up arrow, maybe a box with a down arrow could mean save?

I would merge the idea of saving and bookmarking, because basically they mean "I want to be able to retrieve this"

☆ (unsaved)

★ (saved)

As a symbol, since the humanity is traveling, the stars are used to find what they are looking for or find it back (typically the North Star). And I'm pretty sure it will stay meaningful for a galactic civilisation.

Maybe something like a document going into a safe? As things are increasingly digital, both of those technologies become somewhat less relevant. On the other hand, one could go with 保存 on a button. Chinese and Japanese speakers will instantly know what it does. Others could learn. At some point, kanji are just slightly more complex squiggles to represent an increasingly non-concrete thing.

Anything designed to represent the save action will become obsolete eventually because the nature of saving data changes.

Originally you saved writing by inscribing it on a wax tablet, then paper, then removable disk, then hard disk, then solid state, now the cloud.

I would say the most times less will be pencil on paper as it's the most basic method of recording.

📝

But that's already considered to mean an edit action

A hammer and chisel with a stone slate… some combination of that

📖

Two types:

1. "Save state" like in video games or word processors

• For saving state in current application
• There is hard disc / cloud saving

2. "Save file" like in web browsers

• This is for creating a copy of a file you found and want to keep
• There is hard disc / cloud saving

In both cases you will want to signify saving to disc (this could look like a thick round disc) versus saving to the cloud