There’s a technique in science that’s commonly used called blotting. It is basically exactly what it sounds like. You transfer a biological sample to a sheet of paper by pressing the paper into your sample.

The person who first developed blotting was a guy with the last name Southern, and he did it to transfer DNA into paper. So that became known as a Southern Blot.

Then someone else decided to try the same thing with RNA, and so they called it Northern Blot, because ofc North is opposite of South. Then someone else tried it with proteins, and that became known as a Western Blot. I think now there’s even Northeastern Blots