赤道
せきどう · sekidou · JLPT N2 · noun
equator
🌍 赤道 = 赤 red + 道 road: the red line running around the middle of the Earth
赤 means red and 道 means road or path. The equator is the line around the Earth's middle, halfway between the poles. Same 赤 as 赤色 (red).
道 — 辶 (walk) + 首 (head)
Originally a compound of 辶 'walk/movement' and 首 'head', depicting a path one walks while looking ahead. The literal sense 'road, way' extended metaphorically to 'method, doctrine, the Way (Dao)'. This philosophical meaning became central in Daoist and Confucian thought.