“A locale is a collection of files, data, and sometimes code, which contain the necessary information to adapt Solaris to a specific geographical market. It is essentially a “bundle”, containing information such as the messages displayed to the user, interface component information, for example the size of the buttons; cultural information such as dates and currency formats, and fonts or other writing specific information.”
Only the first of a broad serie of FAQ about Solaris locales. Already contains details about update releases of Solaris 10. Very good info.