Truncation is a search technique used in databases where the ending of a word is replaced by a symbol. This allows different forms of a word to be searched simultaneously and will increase the number of search results found. The asterisk (*) is the most commonly used symbol for truncation, but different databases and search engines have different rules and symbols for truncation, wildcard characters, etc. Using truncation can help you complete your search faster, as you won't have to manually type and search every variation of the word.
It can be used anywhere in the search term, except as the first character. Truncation is very useful when you know that one of your search terms has multiple endings, but all variations represent basically the same idea. In Ovid databases, you can use truncation and wildcard symbols to find variations in spelling and endings of variant words. However, it is important to check the information in the database “Help” or “Search Tips” for details on which symbol to use.
If you don't disable the assignment, Ovid tries to assign truncated terms to subject headers and issues an error message.