Bengali: রাধুনি. I was going through my late dad's spice cabinet looking for kasuri methi, when I found a bag of radhuni. This very fragrant and aromatic spice is unique to Bengali cooking and sometimes used as one of the ingredients of panch phoron where it replaces mustard seeds.
Known in English as "wild celery" it adds a unique and authentic flavor to Bengali dishes such as shukto1. It can be overpowering, so always use it sparingly. I will especially adhere to this advice, because I am not sure if I will be able to refill my supply here in Germany2.
1 https://en.wikipedia.org/wiki/Shukto
2 I do have easy access to several small Indian grocery stores, so maybe one of them carries it