A Wildcard character is a search tool that is used to maximize search results in research databases. They give you the power to search for variations of a search term and can also be used with search engines like Google.
There are two common types of Wildcard operators. The first is the truncation character, which is commonly an asterisk (*). It is typically used at the end of a root word and may specify any number of characters. Most commonly it is used when you want to search for variable endings of a word. For example, searching for educat* would tell the database to look for all possible endings and results could include educate, educated, education, educational and educator.
The second common Wildcard character is used to represent a single letter anywhere in a word. This type of Wildcard character is often a question mark (?) and is most useful when there are variable spellings for a word. For example, if you type advis?r, your results will include advisor and adviser.
Each of the library's databases use Wildcards differently and have additional operators and tools for manipulating your search queries. To find out what works in your favorite database, or search engine, look up the search tools available to you in the Help Section (and yes, believe it or not, even Google has a help section!)