AI engineering glossary · NLP embeddings
What is BILOU tagging?
BILOU tagging (also called BIOES tagging): An extended span-labelling scheme with Beginning, Inside, Last, Outside and Unit tags, where U marks a one-token entity. The extra tags give clearer boundary information and often help sequence models slightly.
BILOU tagging: an example
"Mumbai" alone is U-LOC, while "New Delhi" is B-LOC L-LOC.
Related terms
More NLP embeddings terms
- BIO tagging
- BM25
- Byte-level BPE
- Byte-pair encoding
- Case folding
- Character-level tokenisation
- Chunking
- Co-occurrence matrix
Where you learn it
BILOU tagging is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.