The abbreviation SynAF stands for Syntactic Annotation Framework. It was developed within the eContent LIRICS project and then it has been taken over and developed further by Technical Committee ISO/TC 37 (Terminology and Other Language Resources), Subcommittee SC 4 (Language Resource Management). Since 2010, SynAF has been accepted and ranked as ISO 24615:2010 standard.

SynAF is closely related to ISO 24611 (MAF, morpho-syntactic annotation framework). In contrast to MAF, which describes such features as part of speech, morphological and grammatical features, SynAf describes a word overall analysis. This specifies the syntactic relations existing between single words and how words are arranged and connected to build phrases and sentences. Both specifications are designed to be able to complement to each other.

The objectives of SynAF are to describe a meta-model representing the syntactic annotation of textual documents and to offer a set of data categories, as a basis for unitary syntactic annotation of language resources or language processing components.

By using SynAF, two main kinds of syntactic annotation can be represented: the constituent and dependency structures. SynAF allows to handle syntactic ambiguities and to differentiate between shallow and deep annotations.