Raw fonts
From Webfonts.info
When fonts in the TrueType (.ttf) or OpenType (.ttf/.otf) format are directly linked in web pages they are usually referrered to as “raw fonts“, because they were not converted into a webfont format. The possibility of using raw fonts was first introduced in Safari 3.1 in 2008—later Firefox and Opera followed.
Commercial fonts usually can't be used as raw fonts on websites because of license restrictions. See Web fonts licensing overview for more information.