Endannota

Endannota is a term used in data annotation and natural language processing to designate the end boundary of an annotation span within a text. It complements a start marker and helps ensure that annotated elements have precisely defined limits. In practice, endannota can be implemented as a dedicated boundary token or as a metadata attribute within annotation formats such as JSON, XML, or CoNLL-style sequences.

Origin and usage: The concept arises from the need to disambiguate nested and overlapping annotations in complex corpora. By marking where an annotation ends, endannota supports robust parsing by annotation tools and facilitates conversion between formats that represent spans differently.

Implementation: Endannota may be realized as an explicit end token (for example, an END-ANN marker), a boundary flag in structured data, or as a separate field that accompanies the span. This flexibility allows multi-layer annotations, such as entity and relation labels, to be aligned without conflating their boundaries.

Impact and considerations: Endannota improves precision in span-based tasks like named entity recognition and coreference, aids evaluation by clarifying true span extent, and facilitates interoperability across annotation tools. It requires clear documentation of semantics to avoid confusion with similar markers.

See also: boundary token; span annotation; named entity recognition; data annotation formats.