In general terms, a recipe is a set of instructions that describe how to prepare or make something, with respect to computing it's typically used to describe a set of rules used to manage building code.
The term "recipe" refers to a set of instruction, usually in a standalone text based file, which are interpreted by an application that will use them to execute a build.
Because a "recipe" is a very general term, it should be paired with another tag to help identify what system it is in reference to.
Examples of systems which use recipes:
GNU Makefiles use the term recipe with respect to writing rules for make to interpret.
Bitbake uses recipes files (typically with a .bb extension) which tell bitbake how to fetch code, build dependencies, make configurations, and do installations.
