Raid, as deemed by SE, is content that requires full party but can not simultaneously be a trial (primals). So deal with it. You can argue semantics all day but that doesn't change what SE has set. Also, more than 8 people content would be a nightmare to set up and content is generally dumbed down to accommodate that many people.

The Japanese basically it, "Bahamut's Dungeon: Encounter 1-5" (for Binding Coil turns 1-5) and "Bahamut's Dungeon: Invasion 1-4" (Second Coil of Bahamut turns 1-4).