Picture one long table with things spread all over it, and then somebody stands a board upright across the middle. Nothing was added and nothing was taken away, but now there is a this side and a that side. A divider is always that board: the object standing in the middle that turns one thing into two parts. Change what the table is — a room, a road, a file of paper, a signal in a wire — and you have all the meanings of the word.
From the word’s history
The word is divide plus -er. The ending -er names whoever or whatever does the thing, so a divider is simply the one that divides; because -er covers both people and objects, the same word can name a screen, a strip of road, or a piece of a circuit.
這個字是 divide 加上 -er。-er 的意思是「做這件事的人或東西」，所以 divider 就是「負責分開的那個」。也因為 -er 人和物都涵蓋，同一個字可以指屏風、可以指馬路中間那條，也可以指電路裡的元件。
Wiktionary entry for divider (packet evidence: 'From divide + -er.')
登入就可以看每一支怎麼連回核心畫面。