I've decided to primarily focus on the Covenant for Halo. I like their ships, their lore, and I have a zeal for religious fanaticism.
I've been doing some research about their fleets and organizational structure (I should point out that I'm a big fan of the Halo games but I don't know much about the wider world of Halo. I've only recently read a couple of the stories and watched the short film "Forward Unti Dawn")
When researching I came across an interesting bit about the three letter class designations of the covenant fleet. As it turns out the three letter designation was at first a child of the UNSC but Bungie turned it into a canonical Covenant naming structure.
Each class of ship is designated by a combination of three letters (A, C, D, O, P, S, R, and V). These letters correspond to religious sounding words that then designate certain functions or a specialization within the Covenant fleet.
For instance the ORS-class Heavy Cruiser:
O=Ordained which means the ship has some form of Forerunner technological modification.
R=Reverence which denotes a function, in this case reconnaissance and excavation of Forerunner artifacts.
S=Salvation which means the class is a dedicated warship...I take that to mean it is equipped for pitched battle.
These are actually the only letters that Bungie ever provided a description for, but some Halo fans have come up with educated guesses as to what the other letter and words mean based on the type of ship and what role it tends to play.
For instance, the CCS-class Battlecruiser is the most prolific Covenant ship by far, so some have speculated that the C=a backbone component of Covenant fleets. This would hold true for the CAS-class assault carrier, CPV-class heavy destroyer, and many other C designated Covenant ships. However, the double C seems to perplex everyone. It could be speculated that the double C indicates not only is it the backbone of the fleet but is also the frontline or primary warship of the fleet as well.
