地平線
ちへいせん · chiheisen · JLPT N3 · noun
horizon
🌅 地平線 = earth (地) + flat (平) + line (線): the ground's level line
地 (chi) means ground or earth, 平 (hei) means flat or level, and 線 (sen) means line. Put together, it is the flat line where the earth ends. 水平線 (suiheisen) follows the same pattern and means the horizon at sea.
地 — earth 土 + 也 (phonetic)
地 is a semantic-phonetic compound. The left component 土 means 'earth' or 'soil' and gives the meaning, while 也 on the right hints at the pronunciation. Originally referring to the ground or land, it broadened to mean 'place,' 'region,' and 'territory.'
平 — horizontal stroke 一 + 干 with two dots 八
平 originally depicted a balance or scale being level, suggesting evenness. The horizontal lines and symmetrical dots evoke a flat, balanced surface. Over time it extended from 'level/flat' to broader senses like 'calm,' 'peaceful,' and 'ordinary.'