到底
dàodǐ · HSK 3
after all
🏁 到 = arrive + 底 = bottom; arriving at the bottom means 'at the very end'
到 (dào) means 'to arrive' and 底 (dǐ) means 'bottom' or 'base'. Together they convey reaching the very end or bottom of something — hence 'after all' or 'at last' when pressing for a final answer.
到 — 刂 knife + 至 (phonetic, 'arrive')
到 is a semantic-phonetic compound. 至 ('to arrive') gives both meaning and sound, while 刂 (knife) was added later, likely as a phonetic reinforcer or to distinguish the written form. The core sense 'to arrive, reach' comes directly from 至, and 到 has carried that meaning since early script forms.
底 — 广 (shelter radical) + 氐 (phonetic 'dǐ')
底 is a semantic-phonetic compound. The 广 radical depicts a roofed structure or shelter, suggesting the bottom or base of a building. The component 氐 supplies the sound 'dǐ' and originally meant 'low' or 'base,' reinforcing the meaning. Together they convey 'bottom,' 'foundation,' or 'underneath.'