These are terms we use for keyword search techniques.
Truncation involves using a symbol at the end of a word's root to find every term that starts with that root.
For instance, in TOPCAT we search for econom$ to find "economy", "economic", "economics", and "economical". In most online indexes the symbol used is an asterisk (*): "econom*".
A wildcard is usually used to represent any one letter in a specific place in a word. For instance, in TOPCAT we search for "wom?n" to find "woman" or "women".
See more information about using truncation and wildcards in our keyword searching tutorial.