A chunk is a short phrase within a sentence. If you remember sentence diagrams from grade school, they were a tree-like representation of phrases within a sentence. This is exactly what chunks are: subtrees within a sentence tree, and they will be covered in much more detail in Chapter 5, Extracting Chunks. The following is a sample sentence tree with three Noun Phrase (NP) chunks shown as subtrees:
This recipe will cover how to create a corpus with sentences that contain chunks.
The following is an excerpt from the tagged treebank corpus. It has part-of-speech tags, as in the previous recipe, but it also has square brackets for denoting chunks. The text within the brackets has been highlighted to make the chunks more apparent. The following sentence is the same sentence as in the previous tree diagram, but in text form:
[Earlier/JJR staff-reduction/NN moves/NNS] have/VBP trimmed/VBN about/IN [300/CD jobs/NNS] ,/, [the/DT spokesman/NN] said/VBD...