便道
biàn dào · HSK 7
sidewalk
🚶 便 (convenient) + 道 (road) = a convenient road, the sidewalk
The shortcut or pavement is literally the 'convenience path' — the easy route beside the main road. biàn as in biànlì (convenient), dào as in dàolù (road).
便 — person 亻 + change 更
A semantic compound: 亻(person) beside 更 (to change/replace). The original sense was a person making things easier or more convenient by adjusting them. From 'convenient' it extended to 'then/thereupon' (biàn) and to bodily 'discharge' (as in 大便).
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.