Understanding the meaning of your search is crucial to returning good answers. So to find pages with relevant information, Google's first step is to analyse what the words in your search query mean.
Google builds language models to try to decipher what strings of words we should look up in the index.
This involves steps as seemingly simple as interpreting spelling mistakes, and extends to trying to understand the type of query you’ve entered by applying some of the latest research on natural language understanding.
For example, Google's synonym system helps it know what you mean, even if a word has multiple definitions. This system took over five years to develop and significantly improves results in over 30% of searches across languages.
Google also tries to understand what category of information you are looking for.
Is it a very specific search or a broad query?
Are there words such as “review” or “pictures” or “opening hours” that indicate a specific information need behind the search?
Are you searching for trending keywords that imply you want content published that day?
Or are you searching for a nearby business and want local info?