A recursive Acronym for YAML Ain't Markup Language.

YAML is supposed to be a straightforwardly parsable Serialisation format designed to be very human-readable, easy to implement, and computationally powerful. It is optimized for data Serialisation, but was intended to be directly applicable for storing configuration settings, log files, Internet messaging and filtering. It uses the host languages' native data structures, has a consistent information model, and enables stream-based processing. Implementations are available for many ProgrammingLanguages, including Java, JavaScript, OCaml, Perl, PHP, Python, Ruby, and others more.

In recent times, the format has gotten very complex, and has acquired features that are somewhat tied to Perl. JSON is gaining in favour over it.