Lesson eight of the Kanji series on the official site is the word for this special item that Goku gets from Karin and revives injured fighters in the series. Yes that’s right. The Kanji is 仙豆 or senzu in senzu bean! Sen or the character on the left has the pictogram of a person in the mountain meaning hermit. and the pictogram for zu isn’t as descriptive but you can imagine a seed with roots in the ground as well as dirt above. So senzu literally means hermit bean. You can read more about this character here!