The dictionary markup can be used to store key-value pairs like in a dictionary or glossary. It uses definition lists (see HelpOnLists). A dictionary page used by the system has to have a name ending with Dict (see page_dict_regex on the page HelpOnConfiguration).
Dictionaries can be either shared or private (only you have read access to them under your homepage).
How does it look?
This is an example:
var1
value1
var2
value2
var3
value3
And it looks like this in the page source:
var1:: value1
var2:: value2
var3:: value3
The leading space and the space after '::' are important.
Dictionaries can be used to translate user-specified words with auto-substitution1. If you want to use that a dictionary has to be named in the form LanguageDict (examples: GermanDict, FrenchDict, SpanishDict, etc.).
this is an alternative for the distributed PO-Files, which are used instead in MoinMaster wiki (1)