With the example on the previous page in mind, suppose you have used the search term 'justice' to search for the document you want. Set out below are four documents in the sample database. All four documents would be retrieved if the search term 'justice' were used, because they all contain that key word. But notice that in each document the context and meaning of the word 'justice' is very different.

This may not seem a big problem when the database is so small, but in large databases you may end up retrieving thousands of unwanted documents. That is not efficient.