Many databases allow you to provide a character to represent one or more characters following your term, in order to catch variations of the word and plurals. In most databases (but not all), it is represented by an askerisk symbol (*). For instance:
Would retrieve documents containing the word sefarer, seafarers, seafaring.
A wildcard is a substitution of a single character (or no character) and can be used to catch variations in spelling.
Would retrieve documents with the word "Labor" or "Labour." Wildcard symbols might not be avialable in some databases, and the choice of characters can vary according to database, so be sure to look this up in the help. Truncation and wild cards are fairly surgical means of expanding your search results.