TrueType Collections
Share glyph sets among fonts
A TrueType Collection (.TTC file) is a single file structure that allows multiple TrueType fonts to efficiently share data tables. TrueType Collections can be used when several fonts share many glyphs in common, resulting in a significant reduction in font file space.
For example, a group of Japanese fonts might each have their own designs for the Kana glyphs, but share identical designs for the larger set of Kanji glyphs. With ordinary TrueType font files, the only way to include the common Kanji glyphs is to duplicate the Kanji glyph data in each font. But, with TTCs, several fonts can share a single copy of the Kanji glyphs. Currently, TTCs are supported in GDI for the Far East versions of Windows.