海面
hǎimiàn · HSK 7
sea
🌊 海 sea + 面 surface = the sea's surface
海 (hǎi, sea) plus 面 (miàn, face or surface) compounds to the surface of the sea. The same 面 shows up in 表面 surface and 地面 ground; treat it as the face of something flat.
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).
面 — enclosure 囗 + 自 (nose/face inside)
Originally a pictograph showing a face framed by an outline, with 自 (nose) inside representing the central feature of the face. The early meaning was 'face,' which extended to 'surface,' 'side,' and 'aspect.' In simplified Chinese, 面 also absorbed 麵, adding the meaning 'flour/noodles.'