同～
どう～ · dou～ · JLPT N2 · noun
lapp
🧦 同 = same, so 同級生 = same-grade + student (classmate) and 同時 = same + time (simultaneous)
同 means same or together and starts many compounds. Add the ~ suffix to the rest: 同意 = same + meaning (agreement), 同じ = same + kind (identical).
同 — 冂 enclosure + 一 + 口 mouth
Originally depicted multiple mouths gathered under one cover or enclosure, suggesting people speaking together in agreement. From this image of voices joining, it came to mean 'same,' 'together,' or 'alike.' The shared cover symbolizes unity.