上门
shàng mén · HSK 4
to visit
🚪 上 (shàng, on/up) + 门 (mén, door) = come up to the door
上门 literally means to come up to someone's door — hence to drop in or visit. The opposite sense (to lock up or close shop) comes from putting the bar up on the door for the night.
上 — horizontal line above a baseline
上 is an indicative character (指事): a short stroke placed above a longer reference line shows the concept of 'above' or 'up'. The earliest oracle-bone forms used two horizontal lines for this; the modern shape added a vertical stroke for clarity. The core meaning of 'upper, above, to ascend' has stayed stable for millennia.
门 — pictograph of double-leaf gate
门 is a pictograph showing a pair of swinging doors hung in a doorway, originally drawn as 門 in oracle-bone script with two clear leaves. The simplified form 门 keeps the same outline with fewer strokes. It still means 'gate' or 'door' and serves as a phonetic in characters like 们, 问, and 闷.