Truncation Truncation is like a wildcard. Added to the stem of a word, it will find that stem plus anything that comes after it. The symbol used to truncate a word depends upon the index, database, or Web search engine you are using. psychol? will return records on psychology, psychological, psychologist. ? is used as the truncation symbol, for example, in ProQuest and . environ* will return records on environment, environments, environmental. * is used as the truncation symbol in MIRLYN.