在滑的是東西
同樣的畫面，主角換成桌上的東西：一個在桌面滑動、不用人費力推的小盤子。
noun · B1
A small flat mat that you put under a glass, cup, mug or bottle so that heat, drips, or water running down the outside of the glass do not mark the table.
杯墊
這個拼法底下其實是2個不同的字，意思沒有關係， 只是長得一樣。下面分開列出來。跳到 杯墊 · 沿海貨船
1
coaster
noun核心畫面
Still moving, but nobody is pushing. A bicycle rolling downhill with the feet off the pedals; a little tray sliding across a table from hand to hand. Motion without effort — that is what this coaster names.
這一支的 coaster 可以想成「還在走，但沒有人在使力」。腳踏車下坡，腳離開踏板，車子照樣往前滑。小托盤在桌面上…更多收起
這一支的 coaster 可以想成「還在走，但沒有人在使力」。腳踏車下坡，腳離開踏板，車子照樣往前滑。小托盤在桌面上被推來推去，從這隻手滑到那隻手。有移動，沒出力——這一支的 coaster 講的就是這件事。From the word’s history
This coaster is the verb coast (to glide along without adding energy, to make a minimal effort) plus -er, the agent-noun ending.
這個 coaster 是動詞 coast（不再出力、靠慣性往前滑；做最小程度的努力）加上 -er，也就是「會做這件事的人或東西」。
Wiktionary, entry 'coaster' etymology 2: "From coast (to glide along without adding energy; to make a minimal effort...) + -er (suffix forming agent nouns)." (kaikki:3f6f69a190036ae4:1159393561)
From the picture
Also in this word
noun · C1
Someone who gets through a job or a course by doing only the least that is needed, and still does well enough to get by.
混日子的人；不出力的人
A second word, same spelling
2
coaster
noun核心畫面
Something that keeps to the shoreline. It moves, it works, it carries loads from place to place — but the land is always in sight on one side, and it never turns out into the open sea.
這一支的 coaster 可以想成「貼著岸走的那個」。它一直在動，也在做事，一個港口一個港口地送貨。但是有一邊永遠看…更多收起
這一支的 coaster 可以想成「貼著岸走的那個」。它一直在動，也在做事，一個港口一個港口地送貨。但是有一邊永遠看得到陸地。它不會轉身開進大洋。From the word’s history
This coaster is coast (the edge of the land where it meets the sea) plus -er, the ending that forms agent nouns — so, the one that goes along the coast.
這個 coaster 是 coast（陸地與海相接的邊，海岸）加上 -er（構成「做這件事的人或東西」的字尾），字面就是「沿著海岸跑的那個」。
Wiktionary, entry 'coaster' etymology 1: "From coast (edge of the land where it meets an ocean...) + -er (suffix forming agent nouns)." (kaikki:3f6f69a190036ae4:1159370143)