Another use of fallback fonts arises when one wants to replace the glyphs for some characters in the base font with glyphs for those characters from another font. In such a case, the latter font can be specified as a fallback font.
For example, the following document uses the [[Latin Modern]] font as the base font, and uses the {{code|Asana Math}} font for mathematical script letters, which lie in the Unicode block
{{code|Mathematical Alphanumeric Symbols}}. This document uses the command {{cmd|definefontfallback}} instead of {{cmd|definefallbackfamily}}. The ConTeXt name of the block is supplied as the last setup of this command.