Picture a brush loaded with water touching a block of dry colour, and the colour lifting and running out across the paper. Water is inside this paint, not just beside it: the more water, the thinner and paler the layer, and the more the white paper shows through from underneath. That one see-through layer is the whole word. The name of the paint then travels in the ordinary way names travel — onto the sheet that comes out of it, onto the whole practice of working this way, and even onto the action of doing it.
可以想成一支沾了水的筆碰到乾乾的顏色塊，顏色被水帶起來，在紙上跑開。水不是站在旁邊的配角，它是這種顏料的一部分：水越多，那一層就越薄越淡，底下紙的白就越透出來。整個字的起點就是那一層透明的顏色。接下來這個名字往外走，走法跟其他材料名一樣自然——從顏料走到畫出來的那張紙上，再走到「畫水彩」這整件事上，最後連做這件事的動作也用同一個字。
From the word’s history
From water + colour.
這個字就是 water（水）加 colour（顏色）接起來的。拆開來看，字面已經把用法說完了：要先加水，顏色才化得開、才會透。
Wiktionary entry for watercolour (kaikki:3f6f69a190036ae4:836314204:29600): From water + colour.
登入就可以看每一支怎麼連回核心畫面。