You can picture a bearer as someone with both hands full, walking. Something is resting on them — a flag, a stretcher, a coffin, a load of tents — and their whole job, for that stretch of time, is to keep it up and keep it moving. The word names the person by the weight they are under, not by who they are. Once you can see that, the stranger uses follow easily: the weight can become a message, a passport, a coffin, or a tradition, and the picture still works.
From the word’s history
Wiktionary records bearer as Middle English berer / berere, from Old English berere, and analyses it as bear + -er; the early attestation given is wæterberere, a water-carrier. That is the same picture the modern word keeps: the one doing the bearing.
來源資料記載 bearer 來自中古英文 berer、berere，更早是古英文 berere，結構是 bear 加上 -er，早期例子是 wæterberere（挑水的人）。這條線索跟今天的畫面是同一個：做「扛」這件事的那個人。
Wiktionary entry 'bearer' (packet etymology_text, source_ref kaikki:3f6f69a190036ae4:912054022)
登入就可以看每一支怎麼連回核心畫面。