What exactly is a "binary file"? I suspect this may be more of a concept / theory question, but, I haven't been able to wrap my brain around what exactly a binary file is.

I've read links such as the below:

https://en.wikipedia.org/wiki/Binary_file

https://betterexplained.com/articles/a-little-diddy-about-binary-file-formats/

But, the piece of the puzzle that's confusing me, is that ALL files are stored as 1's and 0's on a hard-disk, or, in RAM, etc.
(i.e. there's no physical engraving of the hex characters "6F" onto a disk platter for example; it's still a binary format that the data is stored in).

So, if all files are stored as binary, then, presumably it's an operating-system, (&amp; filesystem) concept to refer to something as "binary" file?
A binary file is a file that is simply not a text file. It means that a bin file has a specific format (mp3, exe, jpg...) and can not be interpreted only as a character sequence. There are many ways data can be formatted and read.