脑海
nǎohǎi · HSK 7
brain
🧠🌊 脑海 = 脑 brain + 海 sea; the sea of the brain means the mind
脑 (nǎo) is brain and 海 (hǎi) is sea. Chinese frames the mind as a vast sea inside the brain, so 脑海 names the mental space where thoughts surface, like a brain-ocean.
海 — water radical 氵 + 每 (phonetic)
海 is a phono-semantic compound. The 氵 (water) radical signals the meaning—a vast body of water—while 每 supplies the sound. Originally referring to the sea or ocean, it later extended figuratively to mean 'vast' or 'a great quantity,' as in 人海 (a sea of people).