[arscan]

http://remysharp.com/2010/10/08/what-is-a-polyfill/

"Shim, to me, meant a piece of code that you could add that would fix some functionality, but it would most often have it’s own API. I wanted something you could drop in and it would silently work (remember the old shim.gif? that required you actually inserted the image to fix empty td cells – I wanted something that did that for me automatically).

I knew what I was after wasn’t progressive enhancement because the baseline that I was working to required JavaScript and the latest technology. So that existing term didn’t work for me."