Chunking
POS taggers work on individual tokens of words. Tagging individual words isn't always the best way to understand corpora, though. For example, the words 'United' and 'Kingdom' don't make a lot of sense when they're separated, but 'United Kingdom' together tells the machine that this is a country, thus providing it with more context and information. This is where the process of chunking comes into the picture.
Chunking is an algorithm that takes words and their POS tags as input. It processes these individual tokens and their tags to see whether they can be combined. The combination of one or more individual tokens is known as a chunk, and the POS tag assigned to such a chunk is known as a chunk tag.
Chunk tags are combinations of basic POS tags. They are easier to define phrases by and are more efficient than simple POS tags. These phrases are chunks. There will be instances where a single word is considered a chunk and assigned a chunk...