Use the Traditional credit only for writing type credits.
Traditional is not a real composer; it is a credit given for any piece of music where the songwriter is not known and the music has been handed down - usually by rote (word of mouth / copying the music by ear). It is a common credit in music such as blues, folk, jazz, world, and rock (to a lesser extent).
Common abbreviations for this credit are 'Trad' and 'Trad.' or any language variation thereof.
NOTE: If the writer credit is NOT a variation or translation of 'Traditional', please check for an existing artist name, or use the following format as a credit: Written-By [ReleaseCredit] - Traditional
Example: If the release has 'Christmas Carol' as the credit, please first check to make sure it does not exist as an artist name, and then credit it as: Written-By [Christmas Carol] - Traditional
For 'Folk', 'Folklore', or variations/translations, please use Folk and an ANV.
For releases using 'PUBLIC DOMAIN' and variations, please put the information in the notes as per discussion at: