A cityship I've been working for a long time. Its main purpose is to sustain many generations of settlers and the fleet accompanying them. With it they can fly from one galaxy to another in a 250years approximately and then start to colonize it (everything in the ship can be re-used for their new life).
Those cityship always go in group of 4. In the story I have not yet written, there are the Shel'Ata (of course), the Kanir'Ata, the Soo'Ata and the Amanur'Ata cityships. For those that wonder, the suffix "Ata" is synonym of "city" or more broadly "world" (in 250 years, the language evolved a bit)... #city #scifi #ship #space #stargate