One way to hold this word: a sheet pressed so thin out of plant material that light comes through it. That thinness is the whole word. English calls it paper because of how it looks and feels in the hand — flat, pale, stacked in sheets — not because of what it is made from and not because of what you do with it. One kind takes ink and spreads it. One kind takes water and goes soft enough to eat. Same picture, two rooms.
Two branches
寫字畫畫的薄紙
這一支最貼近那個「薄到透光」的畫面。薄，所以吸水；吸水，所以墨一落就散開，成了毛筆畫特有的味道。
noun · B2
A very thin paper used for painting, writing and making artificial flowers. It is made especially in China and nearby countries, from the soft inside of plant stems — rice, but often bamboo or mulberry instead.
畫用薄紙
泡軟了可以吃的薄皮
同樣是薄到透光的一張，只是這一張真的是米做的，而且吸的不是墨，是水。泡軟就從「紙」變成「皮」，可以包東西進去。
noun · B1
A very thin dry sheet made from rice that you can eat. You soak it in water until it goes soft, then wrap food in it. It is used most of all in Vietnamese cooking, for fresh rolls.
米紙／春捲皮