An Apache module that alows a web site administrator to determine how the URLs of incomming HTTP requests are interpreted. Not as powerful as mod_rewrite but not as complicated either.
Rails can be used with mod_alias, but it does not need it. Present usage favours using Routes, which are far more flexible, just as easy to maintain, and more portable.
If you really need to know more about mod_alias see the Apache documentation
category: Glossary