Inner Sphere Designation for Clan BattleMechs
When the Inner Sphere first encountered Clan OmniMechs (and later second-line BattleMechs) they were not privy to the designations each machine was known by among the Clans. They assigned code names based on the appearance or capabilities in order to define the units encountered. Interestingly, even a century later after the Inner Sphere learned the proper name for these units, the initial designations continue in common use.