This part of ISO 24615 describes the syntactic annotation framework (SynAF), a high level model for representing the syntactic annotation of linguistic data, with the objective of supporting interoperability across language resources or language processing components. This part of ISO 24615 is complementary and closely related to ISO 24611 (MAF, morpho-syntactic annotation framework) and provides a metamodel for syntactic representations as well as reference data categories for representing both constituency and dependency information in sentences or other comparable utterances and segments.