做記號的工具
最直白的一種「留下記號的東西」：你握著它，記號就在眼前出現。其他的意思都可以想成從這個看得見的動作再往外走。
noun · A2
A thick pen with a soft felt tip that puts down a wide, strong line, used for writing on a board, on boxes, or on a poster so that the writing can be seen from far away.
麥克筆
核心畫面
Marker is mark with -er on the end, and -er names the thing that does the job. So the whole word can be read as: the thing that leaves a mark. Hold that picture — something is left behind on purpose, and later somebody reads it. The thick pen is the plainest version, because you can watch the mark appear. From there the mark moves off the paper. It becomes a post in a field, a pin on a map, a number in your blood, a promise made in public, a favour remembered. The material changes every time; the job never does. Something is left where it can be found again, and it stands for something that is no longer in front of your eyes.
「marker」是 mark（記號）加上 -er（做這件事的東西），所以整個字可以讀成：留下記號的那個東西。先抓住這…更多收起
「marker」是 mark（記號）加上 -er（做這件事的東西），所以整個字可以讀成：留下記號的那個東西。先抓住這個畫面——有東西被刻意留下來，之後有人會去讀它。那支粗頭的筆是最直白的版本，因為記號怎麼出現你都看得到。接著記號就離開紙面了。它變成田邊的一根柱子、地圖上的一個圖釘、血液裡的一個數字、當眾說出口的一句話、心裡記著的一個人情。材質每次都不一樣，任務從來沒變過：把東西留在找得到的地方，代表某件此刻已經不在眼前的事。From the word’s history
The evidence packet gives the formation directly: marker is mark + -er, where -er goes back through Old English -ere to a Germanic agent ending, itself shaped by Latin -arius. So the word has always named a doer of marking, and every sense here is a different kind of doer.
證據裡直接給了構詞：marker 就是 mark 加上 -er，而 -er 這個字尾經古英文 -ere 一路上溯到日耳曼語的施事字尾。也就是說，這個字從一開始就是在指「做出記號的那一方」，底下每一個意思，只是換了一種做記號的方式。
Wiktionary etymology tree supplied in this evidence packet (source_ref kaikki:3f6f69a190036ae4:1101821535:49382): From mark + -er; -er via Middle English -ere, Old English -ere, Proto-West Germanic *-ārī.
Three branches
被讀出來的記號：位置與跡象
記號離開紙面，留在世界上；重點從「誰畫的」轉成「誰來讀」。一個讀出位置，一個讀出狀態。
noun · B1
An object or sign that is put in a place to show where something is — where a path goes, where a race ends, where a piece of land stops, or where someone is buried.
標示物
留給以後的記號：宣示與欠下的人情
記號這次不指向現在，而指向以後。留下它的人是要讓別人記住：接下來會怎麼樣，或者這筆還沒結清。
noun · C1
If you put down a marker, you say or do something now that makes clear what you mean to do later, or how good you intend to be, so that everyone else can see it.
先放話定調