AI engineering glossary · RAG vector search
What is chunk overlap?
Chunk overlap: Repeating a small number of tokens at the boundary of neighbouring chunks so that a sentence or idea cut by a split still appears whole in at least one chunk. It reduces lost context at boundaries but increases index size and duplicate results.
Chunk overlap: an example
With 500-token chunks and 50-token overlap, the last 50 tokens of chunk 3 are also the first 50 tokens of chunk 4.
Related terms
- Chunk size
- Chunking
- Sliding window chunking
More RAG vector search terms
- Chunk size
- Citation
- ColBERT
- Context ordering
- Context precision
- Context recall
- Context relevance
- Contextual chunk enrichment
Where you learn it
Chunk overlap is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.