Truncation is a technique allowing a computer to search for word variations.
For example, if you were searching for information about "cloning," you would want to search for information about articles that contained the words "clone," "clones," or "cloned" as well as "cloning." However, a computer can only look for the text string/s you tell it to. If you say, "Find 'cloning." It will find "cloning," but it will miss, say, "cloned." However, if you tell the computer to look for the text string "clon," and tell it not to worry about whatever comes after the "n," it will find "cloned," "cloning," "clones," or "clone." This is what the * in Academic Search Elite tells the computer to d--match all the characters before it and not to worry with what comes after it.
Different databases use different characters for truncation. A database's Help page will usually tell you what the truncation symbol is.
Academic Search Elite uses *
Academic Universe uses !
InfoTrac uses *
Ovid uses $