big iron pot, cauldron
鬵 centers on a large metal cooking vessel: a big iron pot or cauldron used for boiling or stewing.
鬵 combines 兓 (likely a phonetic component) with 鬲 (a cauldron or cooking vessel), forming a character for a large pot. The exact historical development of 兓 is uncertain.
The bottom 鬲 is an ancient cauldron shape, and the top 兓 looks like two figures beside a vessel. Picture a giant iron pot so big it takes two people to lift it.
For セン, imagine a giant cauldron filled with a thousand (千, せん) servings of stew: 千 -> セン, and the pot is big enough to feed everyone.