One way to hold this word: catch the mark a moment leaves on you, and hand that over instead of the thing itself. A scene arrives as light, colour and feeling long before you could list what was in it, and this is the choice to keep the arrival and let the details go. Painters do it with strokes of colour, composers with the texture of sound, poets with a single image — different materials, the same trade.
From impression plus -ism. Impression goes back through French to Latin imprimere: im- ('in') plus premere ('to press') — literally a pressing-in, the mark a scene leaves on you.
由 impression（印象）加 -ism（主義、流派）組成。impression 經由法文回到拉丁文 imprimere：im-（進去）加 premere（壓），字面就是「壓進去」。所以印象本來的畫面，是某個景象在你心裡壓出來的一個印子。這個流派要交出來的，正是那個印子，而不是景象的清單。
Wiktionary etymology tree supplied in this packet (source_ref kaikki:3f6f69a190036ae4:1020325457:23486)
One branch
用印象取代細節的風格
三個意思是同一個做法在三種材料上的樣子；名字先在繪畫成立，音樂和詩都是借過去用的。
noun · B2
A style of painting, used especially in France in the 1800s, in which the painter uses colour and light to show how a scene looked and felt at one moment, instead of drawing every detail of its shape.
印象派（繪畫）