surname
籛 is a rare kanji used primarily as a surname. Its standalone meaning is unclear beyond that usage.
籛 combines 竹 (bamboo) with 錢 (coin/money), but the historical reason for this combination is uncertain. It may have originally referred to a bamboo-related object or been used phonetically for a name.
Bamboo 竹 over money 錢: imagine an ancient family name associated with bamboo currency or a bamboo tally used for counting coins.
For セン, picture a person named Sen counting bamboo coins: Sen -> セン, and the bamboo 竹 over money 錢 reminds you of the surname.