海抜
かいばつ · kaibatsu · JLPT N1 · noun
level
🌊⛰️ 海 (sea) + 抜 (pull up, rise above) = how far land rises above the sea
抜 means pull out or rise above, so 海抜 measures how far land rises above the sea. Sea level is the zero point, so 海抜 counts up from the waterline.
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).