The Truetype Font format is used for storing vector fonts. It originated on Macintoshes and WinTel boxes and can be made to work on many other systems as well. Unfortunately there are two slightly different Truetype formats in use; modern Macintoshes can use either, WinTel boxes are restricted to the WinTel type, and other systems can sometimes use either but will usually be restricted to one or the other. Free conversion programs exist to convert between the two.