余分
よぶん · yobun · JLPT N3 · na-adj
extra
🍰 余分 = surplus (余) + portion (分): a leftover portion, so extra
余 means remainder or surplus, as in 余る (amaru, to be left over). 分 means a share or portion. Together they mean a share beyond what's needed, so excess or extra. Yobun can also sound like 'yo, bun!', said to the spare bun nobody asked for.
余 — roof 亼 + wooden post/pillar
Originally a pictograph of a simple thatched shelter or hut supported by a central post, 余 meant 'lodging' or 'temporary dwelling.' It was later borrowed phonetically to write the first-person pronoun 'I/me,' which became its dominant meaning. The 'surplus/remainder' sense developed through its use as a loan for 餘.
分 — knife 刀 + eight 八 (split apart)
分 originally depicted a knife (刀) cutting something into two parts, shown by 八 above (which itself meant 'divide'). The core sense is 'to divide' or 'split', from which extended meanings like 'portion', 'minute', and 'part' developed. Pronounced fèn, it carries the sense of an allotted share.