A font technology that combines TrueType and Type 1 fonts into a common format for cross-platform operation between Windows and Mac. OpenType provides advanced support for glyphs and ligatures that harks back to the days when elegant typography was set by hand. With thousands of TrueType and Type 1 fonts available in OpenType format, OpenType also supports international character sets and Unicode.
From TrueType Open
Introduced in 1996, OpenType is an extension of TrueType Open, which Microsoft developed to supersede TrueType. Like TrueType, OpenType fonts use only one file per font and store TrueType outlines in files with .TTF extensions and Type 1 outlines in .OTF files. Type 1 fonts are compressed into a Compact Font Format (CFF) file. For more information, visit www.adobe.com/type/opentype/main.html. See TrueType
and PostScript fonts