By truncating you can search for several variations of a term. This is handy when, for instance, a word has several different spellings. You truncate by replacing 1 or more characters of a word with a truncation character. Often the truncation character is a *. Other possible characters are a ?, $ or !. The manual of the database in which you are searching will indicate which character is used for this purpose.
Typing a truncation character behind (part of) a word:
This way you'll search for what you have typed and everything that follows after it.
Example: pig* renders: pig, pigs, piggy, pigfarm, pigfood,etc.
Typing a truncation mark before (part of) a word:
This way you look up what you typed and everything that can be in front of that word.
Example: *roses renders: roses, green house roses, red roses,etc.
When you're searching for a specific word that can be spelled several ways a ? can help you out. This will replace a single character.
Example: Behavio?r renders behavior or behaviour. Organi?ation renders organisation and organization.
Tips!
The trick is not to truncate into a word too soon or too late.
For example, if you're looking for information about "pollution", type pollut* and not poll*.
In Google truncation works differently, there a * replaces a whole word.
Example: Google * my life produces among other things. Google ruined my life and Google is my life.