並行
へいこう · heikou · JLPT N2 · noun
side
🛤️ 並 = side by side + 行 = go, so 並行 means going side by side, at the same time
Two rail tracks run side by side without meeting, like two tasks running at once. 並 (naraberu) means line up side by side; 行 (iku) means go or proceed.
行 — crossroads pictograph (left 彳 + right 亍)
行 originally pictured a four-way crossroads in oracle bone script, with two paths meeting. From 'road' it extended to 'walk, go, travel,' and then to 'a row, line' or 'business firm' (read háng). The two halves 彳 and 亍 are the split sides of that ancient crossroads.