You've hit the nail on the head.
The commonly accepted technical interpretation of "embedding" involves images / flash files / movies displayed within the page.... i.e. small things that take up a relatively small portion of the display.
Because of their size, things like pdfs are more typically not seen as embedded as you typically link to them (e.g. a link to example . com / my.pdf ) and the the PDF reader then displays them within your browser window.
That's my point of view anyway !
P.S. it was also not clear what method you were using ... e.g. object, iframe etc.