PTB

PTB is an acronym that can refer to several different things depending on the context. The two most widely recognized meanings are Physikalisch-Technische Bundesanstalt, the German national metrology institute, and the Penn Treebank, a widely used linguistic corpus in natural language processing.

Physikalisch-Technische Bundesanstalt (PTB) is Germany's national metrology institute. It is responsible for establishing and maintaining national measurement standards, disseminating traceable measurements, and conducting research in metrology and related fields. PTB operates facilities in Braunschweig and Berlin and participates in international standardization and calibration networks, providing reference data and supporting scientific and industrial measurement needs.

Penn Treebank (PTB) is a corpus of annotated English text used extensively in NLP research. Initiated by researchers at the University of Pennsylvania, it provides resources such as part-of-speech tags, syntactic parse trees, and, in some versions, semantic annotations. The corpus includes a substantial collection of Wall Street Journal articles and has served as a widely used benchmark for tasks such as parsing, tagging, and language modeling.

Other uses of PTB exist across different domains, including various organizations, projects, or groups that adopt the acronym. Because PTB is ambiguous, the intended meaning is usually clear from the surrounding field, organization name, or accompanying descriptive terms.