同士
どうし · doushi · JLPT N3 · noun
companion
🤝 同士 = same (同) + person/warrior (士): people on the same side
士 originally meant a scholar or samurai. People of the same kind are companions. As a suffix it means 'among each other', so 友達同士 means 'between friends' and 男同士 means 'among men'.
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.