tagging

Tagging is the process of assigning one or more discrete labels to data items so that models and tools can learn from, search, filter, or evaluate them.

In natural language processing (NLP), tagging often means token-level sequence labeling, such as part-of-speech tags, named-entity categories, chunks, or morphological features.

Tagging can be single-label or multi-label, created by humans, rules, or model-assisted pipelines. Its quality is managed with guidelines, inter-annotator agreement, and review.