其余
qíyū · HSK 4
the rest
➕ 其 (its/that) + 余 (surplus) = that-which-remains, i.e. the rest
其 means 'that/those' and 余 means 'surplus, leftover.' Together 其余 literally reads as 'the surplus of that group' — everything else after the main item is named, i.e. the others or the remainder.
其 — top 八 + winnowing basket 其 (originally 箕)
Originally a pictograph of a bamboo winnowing basket, now written 箕 with the bamboo radical added on top. The original form 其 was borrowed phonetically to write the pronoun and particle meaning 'his/her/its' or 'that.' This loan use became dominant, so a new character 箕 was created for the basket meaning.
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.