It is literally only dragoon because of text length limits and then got stuck in the weird Final Fantasy void zone of whether things are considered too canon to fix or primitive technical limitations like Bolt2 instead of Thundara. I honesty have no idea why this was made the former because I think 99.9% of people could probably figure out that Dragon Knight is the same thing, it wasn't even used in the original localization of FF Tactics where it's called Lancer, they did call Freya a Dragon Knight in IX, and nobody gives a fuck what names the trash ass Anthology translation of FFV used so it may as well have only been used for Kain in FFIV until FFXI.
The other fun one is that Dark Knight in English is alternatively a translation, a literal katakana reading, or actually magic swordsman and every once in a while two will appear in the same game and they have to figure out what the fuck to do about it.