Help screen column header Alias
From Joomla! Documentation
- Alias. The internal name of the item, also used in the URL when SEF is activated. Normally, you can leave this blank and Joomla! will fill in a default value. The default value is the Title or Name in lower case and with dashes instead of spaces. You may enter the Alias manually. The Alias should consist of lowercase letters and hyphens (-). No blank spaces or underscores are allowed. Non-Latin characters can be allowed in the alias if you set the Unicode Aliases option to Yes in Global Configuration. If this option is set to No and the title includes non-Latin characters, the Alias will default to the current date and time (for example "2012-12-31-17-54-38").