核心畫面
A sheet of paper with names written on it, kept beside a closed door. The list itself does nothing; being written on it is what keeps you outside. Black marks the side you are put on, the side that is not let through.
可以想成一張寫著名字的紙，就放在一扇關著的門旁邊。名單本身什麼都不做，是「名字被寫上去」這件事讓門對你關起來。bla…更多收起
可以想成一張寫著名字的紙，就放在一扇關著的門旁邊。名單本身什麼都不做，是「名字被寫上去」這件事讓門對你關起來。black 在這裡標的是你被分到哪一邊——被標記、不往來的那一邊。整個字的重量都在後果：上了這張紙，你就不會被錄用、不會被放行、不會被接通。From the word’s history
From black + list: a list marked black, that is, a list of those to be avoided.
由 black（黑）加 list（名單）合成，字面就是一張「黑的名單」，指要避開的對象。這條線索跟今天的用法完全對得上。
Wiktionary entry for blacklist (packet etymology_text: "From black + list.")