A silver lining is literally something which covers the inside of something and is either made of silver or is silver in colour. For example, the inside of a jacket is covered in a thin, slightly shiny material. This is the lining. You can say the jacket has a silk lining or it has a blue lining.

Literally, "Silver lining" would mean lining in silver😁. However, I believe that's not what you meant to enquire. I think you mean to ask of either the origin of the idioms and why is it called "Silver lining". Well, like any other english idioms or be it a terminology, there's always an origin which later gets popularise and thus finds its usage amongst the public. To answer your questions, I can't possibly trace back it's origin but I'd like to believe it possibly could be a result with relation to the weather. As the meaning is somewhere along the lines of "there may be an advantage to a hopeless event". Like your plane flight got delayed because of the weather and you get mad because you can't imagine the thought of waiting for how long and that you can't go back home either because it's way too far. You feel it couldn't get any worse how fate made you always suffer then you hear the news of an airplane crash that left earlier before yours was delayed. Then you look at the glommy weather weather with relief that in the mist of a small inconvenience something much bigger was rewarded. That's just my take😅 and if you made this far, reading every words,congratulations

It's actually very literal - it has nothing to do with the linings of clothing, etc. Imagine (or actually go outside and look) that there is a cloud blocking the sun. The sunlight behind the cloud makes the edges of the cloud look bright, i.e. silver. If you google: cloud silver lining and look at the images you'll see what i mean.

A lining is the cloth on the inside of a coat, for example, or a purse. (I think of a lining as silky material, but it doesn't have to be.) The saying means that you can't see it from the outside, but there is something valuable or desirable there.