rad
rad — 形容詞
- radpositive
- raddercomparative
- raddestsuperlative
1. an informal word used to describe something as very impressive, enjoyable, or st
超酷；超讚
非常棒、令人興奮的（俚語）
an informal word used to describe something as very impressive, enjoyable, or stylish — a slang term especially popular in the 1980s and 1990s, still used today in casual or ironic contexts.
Tariro thought the vintage leather jacket was totally rad.
Tariro 覺得那件復古皮夾克超級酷的。
totally rad — common intensifier collocation
The skate park has a rad design with ramps and half-pipes painted in neon colors.
那個滑板公園的設計超酷，有塗著螢光色的坡道和半管。
Grandma surprised everyone by saying the heavy metal band was 'totally rad'.
奶奶說那個重金屬樂團『超讚的』，讓大家都嚇了一跳。
Beatriz showed me her dad's old record collection, which looked pretty rad.
Beatriz 給我看她爸爸的舊唱片收藏，那些唱片看起來超酷的。
Yael said the movie was rad, so I saw it on Friday night.
Yael 說那部電影超好看，我星期五晚上就去看了一遍。
- lame
slang opposite; describes something disappointing or uncool
文法句型
rad + noun
be + rad
用法筆記
Occasionally used in informal conversation but now carries a dated or ironic tone. Avoid in formal writing. The word is shortened from 'radical', which was used with the same slang meaning.
常見錯誤
rad — 名詞
1. a unit used in physics and medicine to measure how much ionizing radiation is ta
雷得
游離輻射吸收劑量單位
a unit used in physics and medicine to measure how much ionizing radiation is taken in by a material or living tissue; one rad represents 100 ergs of energy deposited in each gram of the exposed substance.
The technician recorded an exposure of 15 rads during the experiment.
技術人員在實驗中記錄到 15 雷得的輻射暴露量。
countable: 15 rads
Workers at the nuclear facility must keep their yearly radiation below 5 rads.
核電廠工作人員每年的輻射量必須控制在 5 雷得以內。
A sudden burst of 50 rads can damage bone marrow and requires immediate medical care.
突然暴露於 50 雷得的輻射可能會損傷骨髓，需要立即就醫。
The soil sample from the test site showed an absorbed dose of only 0.3 rads.
檢測地點的土壤樣本顯示僅吸收了 0.3 雷得的輻射。
Noa checked the dosimeter and noted that the reading had reached 2.5 rads.
Noa 檢查了劑量計，注意到讀數已達到 2.5 雷得。
- gray (Gy)
the modern SI unit; 1 Gy = 100 rad
文法句型
number + rad(s)
用法筆記
The unit 'rad' has largely been replaced in official contexts by the gray (Gy), where 1 Gy = 100 rad. However, 'rad' is still commonly used in older medical literature and some industrial safety guidelines. The plural form 'rads' is always used after numbers.
常見錯誤
2. a short written form for 'root' in mathematics, used in handwritten calculations
根
數學根數的簡寫
a short written form for 'root' in mathematics, used in handwritten calculations to indicate the square root or another root of a number — for example, 'rad 64' means the square root of 64.
The math teacher asked Hoa to write the rad of 121 on the board.
數學老師請 Hoa 在黑板上寫出 121 的根。
rad of [number]
Hamza scribbled 'rad 64 = 8' in the margin of his algebra test.
Hamza 在代數考卷的空白處草寫了『rad 64 = 8』。
In older textbooks, the square root of 144 is sometimes written simply as rad 144.
在舊版教科書中，144 的平方根有時就直接寫成 rad 144。
Liam solved the problem by writing 'rad 81' instead of drawing the square root symbol.
Liam 在解題時寫了『rad 81』，而沒有畫平方根符號。
- root
the full form; 'rad' is simply an abbreviation
- square root
the most common type of root represented by 'rad'
文法句型
rad + number
用法筆記
This informal notation appears mostly in handwritten notes and older textbooks. In modern printed math, the symbol √ is used instead of 'rad'. Not to be confused with the radiation unit 'rad' (which is pronounced the same but has a different meaning).
常見錯誤
❌ Confusing 'rad' (root) with 'rad' (radiation unit). Check the context: math problems use 'rad' for root; physics or medicine texts use 'rad' for radiation dose.
rad — 縮寫
1. a written abbreviation for 'radian' — a standard unit for measuring angles in ma
弧度
角度的度量單位
a written abbreviation for 'radian' — a standard unit for measuring angles in mathematics, where a full circle equals 2π radians.
In geometry, a whole circle measures 2π rad, which is about 360 degrees.
在幾何學中，一個完整的圓是 2π 弧度，約等於 360 度。
2π rad — standard notation for angle measure
In physics class, Mira converted 30 degrees into 0.524 rad.
在物理課上，Mira 把 30 度換算成 0.524 弧度。
The angle of 57.3 degrees is equal to exactly 1 rad.
57.3 度的角正好等於 1 弧度。
Ayesha calculated the sine of π/2 rad on her calculator.
Ayesha 用計算機算出了 π/2 弧度的正弦值。
文法句型
number + rad
用法筆記
The abbreviation 'rad' is used interchangeably with the spelled-out 'radians' after numbers. Always lowercase. No plural form is needed — '2 rad' is correct (not '2 rads').
常見錯誤
2. a written abbreviation for 'radius' — the distance from the exact center of a ci
半徑
圓心到圓周的距離
a written abbreviation for 'radius' — the distance from the exact center of a circle (or sphere) to any point on its outer edge.
A circle with a rad of 5 cm has an area of about 78.5 square centimeters.
半徑 5 公分的圓面積約為 78.5 平方公分。
rad of [measurement] — radius in geometry formulas
The truck needs a turning rad of at least 12 meters.
這輛卡車至少需要 12 公尺的轉彎半徑。
Ayesha calculated the circumference using the rad of the circle.
Ayesha 用圓的半徑計算了圓周長。
The architect specified a window with a rad of 8 feet.
建築師指定窗戶的半徑為 8 英尺。
- r
the standard symbol in formulas; more common than 'rad' in equations
文法句型
rad of + number
用法筆記
Common in technical drawings, geometry problems, and engineering notes. Usually lowercase. The abbreviation 'r' is even more common than 'rad' for radius in formulas (e.g., A = πr²), but 'rad' appears in written text and labels.
常見錯誤
3. a written abbreviation for 'radix' — the base number of a system of counting, su
基數
記數系統的基底數字
a written abbreviation for 'radix' — the base number of a system of counting, such as 10 in the decimal system or 2 in the binary system.
In the decimal counting system that people use every day, the rad is 10.
在人們每天使用的十進位計數系統中，基數是 10。
rad = radix in number-system contexts
Binary has a rad of 2, meaning it uses only the digits 0 and 1.
二進位的基數是 2，表示它只用 0 和 1 這兩個數字。
Computer science's hexadecimal system uses rad 16, with digits 0–9 and A–F.
電腦科學的十六進位系統使用基數 16，以數字 0–9 和字母 A–F 表示。
Liam asked the computer science teacher why the octal system has a rad of 8.
Liam 問電腦科學老師為什麼八進位的基數是 8。
文法句型
rad of + number
用法筆記
Most commonly seen in computer science textbooks and discussions of different number bases. The full term 'radix' is more common in formal writing; 'rad' is an abbreviation used mainly in labels and tables.