Regular Expression

Any given word that can be matched to a list of valid words in a search. However, this can also include special characters (symbols) that can be used as"wildcards".  For example, consider the following mailbox:

Surfing the waves
Computer stuff
Surface tension

If you entered a search query as sur*, itwould return the 1st and the 3rd message.  The asterisk ( * ) acts as awildcard, meaning it can represent any letter or character.