<human>:  Explain what a root word is.
<bot>: Root words are the base or core part of a word. They are the most basic component of a word and often contain a single meaning. Root words form the basis for many other words, with prefixes and suffixes being added to form new words with slightly different meanings. For example, the word 'walk' is a root word, and when the prefix 're-' is added, it forms the word 'rewalk', which has a different meaning. Root words are important for language understanding, as they are the parts from which more complex words are derived.