土台
どだい · dodai · JLPT N1 · noun
foundation
🧱 土 (earth) + 台 (stand, platform) = a platform set on the earth: a foundation
The earth is the base that a building rests on. Dodai is the layer that holds up everything above it, like a platform on solid ground.
土 — pictograph of a mound of earth on the ground
土 is a pictograph showing a lump or mound of soil resting on the ground line. In oracle bone script it depicted an earthen heap, sometimes interpreted as an altar to the earth god. The meaning has remained stable: earth, soil, or ground.
台 — mouth 口 + 厶 (private)
Originally depicted a raised platform or terrace, suggesting elevation and a place to stand. The character later extended to mean stage, podium, or station. In modern usage it also serves as the simplified form of 臺 (platform) and 颱 (typhoon), and names Taiwan (台灣).