Visitors ask..."What is a Greater Feria?"
I strictly use the Ordo of the F.S.S.P. found linked in the "header above" and linked also here. The Ferias of the next several days are listed as the "Greater Ferias."
The reason for this designation is that these Ferias use the marvelous "O Antiphons" of antiquity. Check, for example info here, and also here.
By the way, I found an online Ordo here for the many who are searching for one which one can download to a calendar or into Microsoft. It seems to be a nice tool. [No warranty is expressed or implied, however!]. I personally like the "book" format of my spiral bound F.S.S.P. Ordo just purchased...