把東西或人墊高的台子
方向一樣是往上，只是這一家自己不動，而是讓放在上面的東西升高。
noun · B2
Risers are a set of wide wooden or metal steps that can be carried from place to place, so that a group of people can stand on them at different heights and all be seen.
階梯台／合唱台
核心畫面
Take 'rise' and add -er: the one that goes up. Sometimes the thing itself travels upward — a pipe climbing through a building, a person getting out of bed. Sometimes it stands still and takes something else up with it — the upright face of a , a block under a screen, a set of steps under a back row of singers. Either way, the picture points in one direction, and that direction is up.
「riser」可以想成 rise（往上）加上 -er（做這件事的那一個）。有時候是它自己往上：一根管子從一樓通到頂樓…更多收起
「riser」可以想成 rise（往上）加上 -er（做這件事的那一個）。有時候是它自己往上：一根管子從一樓通到頂樓，一個人早上從床上起來。有時候它自己不動，卻把別的東西帶上去：樓梯上立著的那一面、螢幕底下那一塊、後排歌手腳下的那一組台子。不管是哪一種，畫面都只指同一個方向，就是往上。From the word’s history
The supplied Wiktionary entry gives riser as Middle English ryser, risere, equivalent to rise + -er. The modern senses are still just that: the one that rises, or the one that raises.
Wiktionary 記的是中古英文 ryser、risere，等於 rise 加 -er。今天的各種用法其實還停在這個字面上：往上的那一個，或是把東西弄上去的那一個。
Wiktionary entry for 'riser' as supplied in this evidence packet: 'From Middle English ryser, risere, equivalent to rise + -er.'
From the picture
早上起來的人
同一個 -er 用在人身上：從床上「起來」的那一個，差別只在起得早還是晚。
noun · B1
Used in 'an early riser' or 'a late riser' to describe someone by the time they usually get out of bed in the morning.
早起／晚起的人
Also in this word
noun · B2
The upright flat part of a step on a staircase — the piece that stands between the step you put your foot on and the next one up.
樓梯豎板
noun · C1
A pipe or channel that runs straight up through a building from one floor to the next, carrying water, gas, or cables.
立管