附加
fùjiā · HSK 7
additional
➕ 附 fù (attach) + 加 jiā (add) = attach and add → append, additional
附 means to attach or adhere (the 阝 radical hints at a mound/place where something is affixed). 加 means to add. Together: tack on extra, supplement, append — like a suffix attached to a word.
附 — 阝(mound) + 付 (fù, give/attach)
A semantic-phonetic compound: the 阝 'mound/hill' radical hints at meaning while 付 'fù' supplies the sound. Originally referred to a small mound or hill附属 to a larger one, which extended to the modern senses 'attach, append, be near'.
加 — force 力 + mouth 口
加 is traditionally analyzed as a compound of 力 (strength) and 口 (mouth), suggesting boasting or exaggerating one's effort with words. From this it extended to the meaning 'to add' or 'increase'. Today it is used broadly for addition, both literal and figurative.