The "Match type" control allows you to indicate how the search pattern is used.
"Exact" tries to match the whole item.
"Starts With" matches entries that start with the item.
"Ends With" matches entries that end with the item.
"Contains" matches entries that contain the item.
"Reg Ex" matches entries using a standard regular expression pattern.
"Parse Best" lookup multiple words in best-matching phrase or sentence.
"Parse All" lookup all possible words in a phrase or sentence.
In regular expressions, use '^' at the beginning to match the start, '$' at the end to match the end, '.*' to match any sequence, '.' to match one character.
(Do an internet search of "regular expression reference" to learn more about regular expressions.)
The local/remote checkboxes determine whether to lookup dictionary or media in the local database or remotely on the server. The latter requires an internet connection.