This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
墡 combines 土 (earth) with 善, which likely contributes the sound. The exact historical development is uncertain.
The left side is earth 土, and the right side is 善 (good). Picture good earth, but its exact meaning is unclear.
For セン, imagine a cent (coin) buried in good earth: cent -> セン, and the earth holds it.