caster 施法者／投擲者／鑄造者｜字脈

核心畫面

One way to hold caster: it names the thing that does the casting. The -er ending simply says , and cast runs along two tracks. On one track, cast means to throw or send something out, and that gives the person who casts spells or pours bronze, and the little pot that shakes sugar out over a cake. On the other track sits an older use of cast that has since dropped out of English, meaning to turn. Follow that one and you reach the small wheel under a chair that swings to face any direction, and then the angle a car engineer uses to describe how a front wheel swings.

caster 可以想成「做 cast 這件事的那個東西」。-er 只是說「做的那一位」，而 cast 本身有兩條線。…更多收起

caster 可以想成「做 cast 這件事的那個東西」。-er 只是說「做的那一位」，而 cast 本身有兩條線。第一條線是「丟出去、撒出去」。順著它，就出現了施法的人、把熔銅倒進模子的師傅，還有桌上那個把糖抖到蛋糕上的小罐子。第二條線是 cast 一個已經退出日常英文的舊意思「轉動」。順著它，就出現了椅子底下那顆會自己轉方向的小輪子，再往前一步，就是汽車工程師用來描述前輪繞著什麼角度轉的那個數字。兩條線都從同一個字根長出來，只是一條在講送出去，一條在講轉起來。

From the word’s history

Wiktionary derives the word from cast plus -er, and states that the wheel sense comes from an obsolete use of cast meaning to turn.

維基詞典把這個字拆成 cast 加上 -er，並指出輪子那個意思來自 cast 已經不用的舊用法「轉動」。

Wiktionary entry 'caster' (noun), packet source_ref kaikki:3f6f69a190036ae4:815482027

Three branches

做出 cast 這個動作的人或機器

這一族最貼近字面：cast 加 -er，就是做那件事的人或機器，其他用法都是從這個造字方式再走出去的。

noun · C1

A person or machine that casts something: someone who throws it, someone who sends it out, or someone who shapes hot metal in a mould. It nearly always comes with more words around it, such as a spell caster, a caster of stones, or a bronze caster.

施法者／投擲者／鑄造者

會自己轉方向的小輪子

這一族走的是 cast 的舊意思「轉動」，所以重點不在滾，而在能不能轉向。

noun · B2

A small wheel fixed under a piece of furniture, such as a chair, a bed or a trolley, so that you can push the furniture along and turn it in any direction.

腳輪／萬向輪

把糖鹽撒出去的小罐子

回到 cast 的第一條線「撒出去」：這個東西不是自己動，而是把裡面的東西送出去。

noun · C1

A small container with holes in the top, used for shaking sugar, salt or pepper over food. This use is mainly British English.

調味罐／糖罐

原始詞典資料7 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。

Castername

1
A surname.

casternoun/ˈkɑːstə(ɹ)/

1
Someone or something that casts.
- a caster of spells
- a caster of stones
2
A wheeled assembly attached to a larger object at its base to facilitate rolling. A caster usually consists of a wheel (which may be plastic, a hard elastomer, or metal), an axle, a mounting provision (usually a stem, flange, or plate), and sometimes a swivel (which allows the caster to rotate for steering).
- Many office chairs roll on a set of casters.
- I have my own phone, an electric typewriter and a lovely chair with casters. The floor is carpeted, the lighting is very adequate.
3
A shaker with a perforated top for sprinkling condiments such as sugar, salt, pepper, etc.
- a set of casters
- Your waiter having settled that point, returns to array your tablecloth, with a table napkin folded cocked-hat-wise (slowly, for something out of window engages his eye), a white wine-glass, a green wine-glass, a blue finger-glass, a tumbler, and a powerful field battery of fourteen casters with nothing in them; […]
4
A stand to hold a set of shakers or cruets.
5
automotivetransportvehiclesThe angle of the axis around which a car's front wheels rotate when the steering wheel is turned, with a vertical axis being defined as zero caster.
- In addition, caster helps to reduce steering effort and to return the steering wheel to the center position after a turn.

casterverb/ˈkɑːstə(ɹ)/

1
To act as a caster

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。