物理上的摩擦
這一支就是核心畫面的字面版本：真的有兩個表面在接觸、在磨。一個講那股「力」，一個講那個「動作」。
physical friction (force) · noun · C1
A natural force between two surfaces that makes it hard for one to slide over the other.
摩擦力
核心畫面
A useful picture: two surfaces pressed together, and one is trying to move across the other. Something invisible resists — the movement is not free, it drags, it heats up, and if it keeps going, something wears down. Friction is that resistance where two things touch and try to move past each other.
兩個面貼在一起，其中一個想要滑過另一個，卻有一股看不見的力量在拖住它。動作不再順暢，會卡、會發熱，磨久了還會磨損。f…更多收起
兩個面貼在一起，其中一個想要滑過另一個，卻有一股看不見的力量在拖住它。動作不再順暢，會卡、會發熱，磨久了還會磨損。friction 講的就是「兩個東西接觸、又想錯開時，中間產生的那股阻力」。有趣的是，人跟人之間也是這樣：要一起做事就得接觸，一接觸、方向又不一致，就會磨出熱來。From the word’s history
From Latin frictio, 'a rubbing, a rubbing down', from fricare 'to rub'. The oldest sense is the plain physical act of rubbing; the force and the human tension are both later readings of that same rubbing.
來自拉丁語 frictio，意思是「摩擦、搓揉」，動詞是 fricare（搓、擦）。最早的意思就是最實在的那個動作——搓、擦、磨。後來科學拿它去命名那股阻力，日常語言又拿它去講人跟人之間的不合；但三個用法底下都是同一個動作：貼著、蹭著、磨著。
Online Etymology Dictionary / Wiktionary (friction ← Latin frictio ← fricare 'to rub')
Two branches
人與人之間的摩擦
把兩個表面換成兩個人：非得共事、方向卻不一樣，於是彼此卡著、磨著，關係開始發熱。
disagreement/tension · noun · C1
Disagreement, angry feelings, or unfriendliness between people who have to deal with each other.
摩擦
原始詞典資料5 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。
frictionnoun/ˈfɹɪkʃən/
- 1
The rubbing of one object or surface against another.
- Energy has seldom been found where we need it when we want it. Ancient nomads, wishing to ward off the evening chill and enjoy a meal around a campfire, had to collect wood and then spend time and effort coaxing the heat of friction out from between sticks to kindle a flame.
- 2
natural-sciencesphysical-sciencesphysicsA force that resists the relative motion or tendency to such motion of two bodies in contact.
- Secondly, When a body is once in motion it will continue to move forever, unless something stops it. When a ball is struck on the surface of the earth, the friction of the earth and the resistance of the air soon stop its motion.
- 3
obsoletemedicinesciencesA massage of the body to restore circulation.
- The frictions should at first be very gentle, and performed with a view to restore heat, and not to force the blood towards the heart, which in drowned persons is already too much distended with it.
- The frictions are made at bedtime, on a limited portion of the body, and on one side only—the calf of the leg by preference, or the thigh, groin, or axilla. It is enough to continue rubbing for from three to five minutes at most.
- 4
Conflict, as between persons having dissimilar ideas or interests; clash.
- Thais have been watching for signs of friction between the armed forces and the monarchy—the country's two biggest sources of political power—since the death in October of Bhumibol Adulyadej, King Vajiralongkorn's long-reigning father.
- Once finances are stabilised, getting Crossrail finished is Byford's most obvious task. Late and over budget, it is causing unwanted headlines and friction between the London Mayor and the Department for Transport that both sides would rather live without.
- 5
historicalConflict during the Second Sino-Japanese War, as between the Communists and non-hanjian Kuomintang forces.
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。