1. the distance around the outer boundary of a circle
圓周長；圓周
To find the circumference of a circle, multiply the diameter by pi.
要計算圓的周長，將直徑乘以圓周率。
The circumference of the Earth at the equator is approximately 40,075 kilometers.
地球在赤道的周長大約是40,075公里。
Circumference Meaning（定義、用法、例句與發音）
circumference
noun
快速理解
What does "Circumference" mean?What are 2-3 core uses of "Circumference"?
Circumference 主要指圓形物體外圍的長度，也可指任何形狀的周邊或邊界。
- 1
幾何定義
EN: The distance around the edge of a circle.
翻譯: 圓形邊緣的總長度。
- 2
計算公式
EN: Calculated as π times the diameter, or 2π times the radius.
翻譯: 計算方式為圓周率乘以直徑，或 2π 乘以半徑。
- 3
外圍邊界
EN: The boundary line enclosing a circular or rounded area.
翻譯: 環繞圓形或近似圓形區域的邊界線。
- 4
廣義周長
EN: The perimeter or outer boundary of any shape or object.
翻譯: 任何形狀或物體的外圍邊界或周長。
小提醒：注意：Circumference 專指「周長」的長度，是一個線性測量值（如公分、公尺），而非指「圓周」這個圓形曲線本身。在非數學語境中，它也可泛指任何物體最外圍的一圈。
發音（How to Pronounce "Circumference" in English）
How to pronounce "Circumference" in English?"Circumference" US vs UK pronunciation
點擊下方的 US / UK 按鈕可播放發音。
Real-life Examples of "Circumference" from YouTube Videos
A theory of everything | Garrett Lisi
TED
“This enormous machine -- the Large Hadron Collider at CERN in Geneva -- has a circumference of 17 miles and when it's operating, draws five times as much power as the city of Monterey.”
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Definitions（定義）
What are the definitions of "Circumference"?How does "Circumference" change by context?
2. the outer boundary or perimeter of any rounded or curved shape or object
（任何圓形或曲線物體的）外緣，周界
The ancient tree had a massive circumference that took three people to hug.
那棵古樹的樹幹周長非常巨大，需要三個人才能環抱。
She measured the circumference of her waist before starting the fitness program.
她在開始健身計畫前測量了自己的腰圍。
3. the area or scope that surrounds or encloses something; the outer limits
範圍；周圍區域
The city expanded rapidly, pushing its circumference further into the countryside.
這座城市迅速擴張，將其範圍進一步推向鄉村。
His influence extended far beyond the immediate circumference of his office.
他的影響力遠遠超出了他辦公室的直接範圍。
Grammar & Patterns（句型）
What are common sentence patterns for "Circumference"?How to make natural sentences with "Circumference"?
| Pattern | Meaning | Example |
|---|---|---|
| the circumference of + noun | ...的周長 | The circumference of the Earth is approximately 40,075 kilometers. (地球的周長大約是40,075公里。) |
| have a circumference of + measurement | 周長為... | The circular track has a circumference of 400 meters. (這個圓形跑道周長為400公尺。) |
| measure/calculate the circumference | 測量/計算周長 | We need to measure the circumference of the tree trunk. (我們需要測量樹幹的周長。) |
| in circumference | 周長為... | The ancient stone circle is over 100 meters in circumference. (這個古老的石圈周長超過100公尺。) |
用法說明
How is "Circumference" different from similar structures?What usage mistakes are common with "Circumference"?
circumference 與 perimeter 的區別
- circumference 專指圓形或橢圓形的周長，是繞著一個圓形物體外緣的完整長度。
- perimeter 則指任何封閉平面圖形（如正方形、三角形、多邊形）的周長，適用範圍更廣。
- 在數學和幾何學中，這兩個詞的區分很嚴格，但在日常口語中，有時會被混用。
- 計算公式不同：
circumference = π × diameter或2 × π × radius；而perimeter的計算公式則取決於圖形的邊長總和。
對比例句： EN: The circumference of the circle is 31.4 centimeters. 翻譯: 這個圓的周長是31.4公分。
EN:We need to measure the perimeter of the rectangular garden to buy enough fencing.
翻譯:我們需要測量這個長方形花園的周長，才能買到足夠的圍籬。
總結建議
在描述圓或圓形物體的周長時，應使用 circumference；對於其他形狀，則使用 perimeter。
易混淆對比
What is the difference between "Circumference" and similar words?How to choose "Circumference" vs alternatives?
circumference vs perimeter
「circumference」專指圓形或橢圓形的周長，而「perimeter」則用於任何封閉平面圖形的周長。
circumference vs diameter
「circumference」是圓周的總長度，而「diameter」是穿過圓心、連接圓上兩點的直線長度。
circumference vs radius
「circumference」是圓周的總長度，而「radius」是從圓心到圓周上任意一點的距離。
口語用法
How is "Circumference" used in spoken English?What is the spoken vs formal difference for "Circumference"?
引述
在口語中，當引述或提及一個剛學到或聽到的概念時，會直接使用英文原詞，以確保所指明確。 EN: I was reading about it, and the article kept mentioning the circumference of the circle. 翻譯: 我當時正在讀相關資料，那篇文章一直提到圓的 circumference。
EN:The teacher said the key formula is pi times diameter for the circumference.
翻譯:老師說關鍵公式是圓周率乘以直徑來求 circumference。
語氣強調
在解釋或強調一個幾何概念的精確性時，會使用這個詞來凸顯其專業性或準確性，與更口語的「一圈的長度」區分。 EN: No, you need the exact circumference, not just a rough estimate around the edge. 翻譯: 不對，你需要的是精確的 circumference，不只是邊緣的大概長度。
EN:The most important measurement for the tire is its circumference.
翻譯:對這個輪胎來說，最重要的測量數據是它的 circumference。
停頓填充
在思考如何用中文表達或組織句子時，可能會先說出英文術語作為停頓點，然後再給出解釋或翻譯。 EN: So the distance around... uh, the circumference... is about 31.4 centimeters. 翻譯: 所以繞一圈的距離... 呃，circumference... 大約是31.4公分。
EN:We calculated the, what's the word, circumference, and then compared it to the diameter.
翻譯:我們計算了那個，叫什麼來著，circumference，然後把它和直徑做了比較。
正式寫作注意：在正式的中文學術報告或文章中，應使用標準譯名「圓周」或「周長」，避免直接嵌入英文 "circumference"，以符合文體規範。
常見短語
What common collocations use "Circumference"?What fixed phrases with "Circumference" should I remember?
the circumference of a circle
the circumference of [object]
圓的周長
measure the circumference
verb + the circumference
測量周長
in circumference
[measurement] + in circumference
周長為...
calculate the circumference
verb + the circumference
計算周長
around the circumference
preposition + the circumference
沿著周邊
circumference and diameter
circumference and [related term]
周長與直徑
large/small circumference
adjective + circumference
大/小周長
常見錯誤
What are common mistakes with "Circumference"?Which "Circumference" sentences look correct but are wrong?
×The circumference of the circle is 10 cm diameter.
✓The circumference of the circle is 10 cm.
Circumference is a length measurement, not a type of measurement like diameter. Do not add "diameter" after the number.
×We measured the circumference around the square.
✓We measured the perimeter of the square.
"Circumference" specifically refers to the distance around a circle or a curved object. For polygons (like squares, triangles), use "perimeter".
×The tree has a large circumference.
✓The tree has a large trunk circumference. / The tree trunk has a large circumference.
While "circumference" can describe the measurement around a tree trunk, it's more natural and clear to specify what the circumference refers to (e.g., trunk, waist, wheel).
×What is the circle's circumference area?
✓What is the circle's circumference?
"Circumference" is the linear distance around a circle. "Area" is the space inside it. They are two different concepts. Do not combine them.
×The circumference is long.
✓The circumference is large / great.
We describe a circumference (a length) as being "large," "small," "great," or a specific measurement (e.g., 10 meters). We do not typically use "long" or "short" for circumference.
×He walked the full circumference of the park.
✓He walked around the perimeter of the park.
"Circumference" is a precise mathematical term for circles/curves. For walking around a general area (which may not be a perfect circle), "around the perimeter" or simply "around" is more natural.
詞形變化
What are the word forms of "Circumference"?What are tense/participle forms of "Circumference"?