比賽裡定速度的人或馬
這一支就是核心畫面本身，最看得見、也最容易記。
noun · C1
A runner, rider or horse who goes at the front of a race and sets the speed that the others try to match.
領跑者
核心畫面
One way to hold this word: someone at the front, holding a steady speed that everyone else moves to. Look at the shape of the word and it is already there — pace plus maker, the thing that makes the speed. In a race that is a runner nobody expects to win; in a chest it is a patch of cells, or a small machine, at the right rate. The pacemaker never does the moving. It only says how fast.
可以想成一個跑在最前面、把速度定下來的角色。這個字拆開就看得到：pace（步調）＋ maker（做出它的人或東西）。…更多收起
可以想成一個跑在最前面、把速度定下來的角色。這個字拆開就看得到：pace（步調）＋ maker（做出它的人或東西）。在比賽裡，那是一位不打算奪冠、只負責帶速度的跑者；在胸腔裡，那是一小群細胞，或一台醫生放進去的小機器。共通點是：它自己不完成那件事，它只決定「多快、什麼時候」，其他人和其他部位照著走。From the word’s history
The word is simply pace plus maker: the thing that makes the pace.
這個字就是 pace 加 maker：定出步調的那個東西。字面和意思幾乎完全重疊，所以拆開來看最好記。
Wiktionary etymology for pacemaker supplied in evidence packet (kaikki:3f6f69a190036ae4:1172273633): From pace + maker.
Two branches
心臟裡的節拍：先是細胞，後是機器
把「定速度的那個角色」放進身體裡：心臟需要有人喊拍子，喊拍子的就叫 pacemaker。
noun · C2
The small group of cells inside the heart that produce the signal which makes it beat; the heart's own natural timer.
節律細胞（心臟本身的）
原始詞典資料3 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
pacemakernoun/ˈpeɪsˌmeɪkəɹ/
- 1
anatomymedicinesciencesSpecialized cells which stimulate the heart to beat.
- natural pacemaker
- cardiac pacemaker
- 2
medicinesciencesA medical implement that is used to stimulate a heart to beat by simulating the action of the natural pacemaker.
- artificial pacemaker
- High intensity EMF can have adverse impacts on the operation of implantable medical devices (IMDs) such as pacemakers and defibrillators.
- 3
One who sets the pace in a race, to guide the others.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。