Trigram search is a method of searching for text when the exact syntax or spelling of the target object is not precisely known or when queries may be regular expressions. Two strings with many shared trigrams can be expected to be very similar. A threshold for number of trigram matches can be specified as a cutoff point, after a result is unmatched. in search engines such as Elasticsearch, as well as in databases such as PostgreSQL.
Examples
Consider the string "alice". The trigrams of the string would be "ali", "lic", and "ice", not including spaces.