Mars and Jupiter have two names, as do other planets in our solar system. There's the "scientific" name and the nickname that the Klingons learned after encountering and engaging with Terrans. In talking with Terrans, or in Terran-y contexts, the nicknames are more common.In a separate list, Okrand gave the scientific name for Mars as Sol loS and Jupiter as Sol vagh.
(Marc Okrand to Jack bradley for In The Year 2889)