pi
/paɪ/ (bre, ipa) · [pˈaɪ] /paɪ/ (ame, ipa) · [pˈaɪ] /ˈpī/ (ame, mw)
pi — 名詞
- pisingular
- pisplural
1. the fixed number, about 3.14, produced by dividing a circle's outer edge length
圓周率
圓形計算用的固定數值
the fixed number, about 3.14, produced by dividing a circle's outer edge length by the straight line through its centre; it is basic in circle calculations.
Ms. Lin wrote pi beside 3.14 on the whiteboard.
Lin 老師在白板上把圓周率 pi 寫在 3.14 旁邊。
pi is about 3.14
Using pi, Aaron found the pond's area for the garden plan.
Aaron 用圓周率算出了花園設計裡那個池塘的面積。
use pi to calculate area
The phone app stores pi to many digits for science homework.
那個手機 app 為了自然作業存了很多位的圓周率。
Without pi, Maya could not measure the bike wheel correctly.
沒有圓周率，Maya 就沒法正確量出腳踏車輪子的尺寸。
- circle constant
technical term for the same mathematical number
- Archimedes' constant
formal mathematical name, much less common in school use
- 3.14
a short rounding, not the exact value
文法句型
value of pi
use pi to calculate + circle measurement
pi is about 3.14
用法筆記
Often written with the Greek symbol π or with the Roman spelling pi in English text. Distinguish from sense 2: here the word names the number, not the alphabet letter itself.
常見錯誤
2. the name or symbol for the sixteenth character in the Greek alphabet.
pi字母
希臘字母表第十六個字母
the name or symbol for the sixteenth character in the Greek alphabet.
In class, Dr. Hsu asked everyone to copy pi and sigma.
課堂上，Hsu 博士要大家抄下 pi 字母和 sigma。
write/copy pi
The old book marks each chapter with a large red pi.
那本舊書用一個大紅色的 pi 字母來標示每一章。
On the chart, pi comes after omicron and before rho.
在圖表上，pi 排在 omicron 後面、rho 前面。
Lena wore a badge shaped like pi at the language fair.
Lena 在語言展上戴了一個像 pi 字母的徽章。
- Greek character
broad term for any symbol in the Greek alphabet, not only pi
- symbol
much wider in meaning and only works when the context already makes pi clear
文法句型
the letter pi
write/copy pi
pi comes after omicron
用法筆記
Usually appears when people are naming or writing Greek symbols. Distinguish from sense 1, where pi names the mathematical value built from this letter.
常見錯誤
3. a short way of writing private investigator, a detective hired by private people
私家偵探
私家偵探縮寫
a short way of writing private investigator, a detective hired by private people or companies rather than by the police.
The worried husband hired a PI to follow the missing driver.
那位焦急的丈夫雇了一名私家偵探去跟蹤失蹤的司機。
hire a PI
By noon, the PI had already checked three hotels near the station.
到中午前，那名私家偵探已經查了車站附近三家旅館。
At the motel, the PI paid cash for a room near Leo.
在汽車旅館裡，那名 PI 付現租了 Leo 附近的一間房。
The film ends when the PI shows the judge new photos.
電影結尾時，那名私家偵探把新照片交給法官。
- private investigator
the full form; PI is the short version
- detective
broader and can also mean a police detective
- sleuth
informal and often playful
文法句型
hire a PI
the PI + past verb
PI report
用法筆記
Usually written as PI in capitals in stories, ads, and receipts. Distinguish from sense 4: this meaning is about detective work, not academic research.
常見錯誤
4. a short way of writing principal investigator, the main researcher who is in cha
計畫主持人
研究計畫負責人的縮寫
a short way of writing principal investigator, the main researcher who is in charge of a science or engineering project.
Dr. Chen signed the grant form as the study's PI.
Chen 博士以計畫主持人的身分在補助表上簽名。
the PI of a study
Before hiring students, the PI checked the lab budget twice.
在聘學生之前，PI 先把實驗室預算核對了兩次。
At the meeting, our PI explained why the robot tests stopped.
會議上，我們的計畫主持人說明了機器人測試為何中止。
The hospital named Sara Kim the PI for the vaccine project.
那家醫院指定 Sara Kim 擔任疫苗計畫的計畫主持人。
- principal investigator
the full form used in formal research writing
- lead researcher
plain description of the person in charge
- project lead
broader and can be used outside scientific research
文法句型
the PI of a study
name somebody the PI
our PI said + clause
用法筆記
Usually written as PI in capitals on grant forms, lab documents, and project emails. Distinguish from sense 3: this PI runs research rather than investigations for clients.
常見錯誤
5. a short way of writing profitability index, a finance number used to judge how s
獲利指數
評估專案獲利的指標縮寫
a short way of writing profitability index, a finance number used to judge how strongly a project is expected to earn money.
The report says the solar plan has a PI above one.
報告說，這個太陽能方案的獲利指數高於一。
PI above one
When costs rose, the PI fell below the bank's target.
成本上升後，PI 跌破了銀行的目標值。
PI below one
Our teacher used PI to compare two factory projects.
老師用獲利指數比較兩個工廠專案。
In the spreadsheet, PI appears next to payback time and risk.
在試算表裡，PI 列在回收期和風險旁邊。
- profitability index
the full finance term; PI is the standard abbreviation
- investment ratio
a looser descriptive phrase rather than the fixed label
文法句型
PI above one
PI below one
calculate PI for a project
用法筆記
Common in finance reports beside numbers such as 1.1 or 0.9. A value above 1 usually suggests the project is worth more than it costs.
常見錯誤
6. a short way of writing professional indemnity, business insurance that helps pay
專業責任險
保障專業失誤求償的保險
a short way of writing professional indemnity, business insurance that helps pay when a client says professional work caused a loss or problem.
The architect renewed her PI before signing the hotel contract.
那位建築師在簽飯店合約前更新了她的專業責任險。
renew PI
Without PI, the small design firm could not bid today.
沒有 PI，這家小型設計公司今天就不能投標。
The broker advised Malik to raise his PI after two claims.
經紀人建議 Malik 在兩次求償後提高 PI 保額。
The firm's PI paid the legal bill after a client complaint.
客戶投訴後，那家公司的 PI 支付了那筆法律費用。
- professional indemnity insurance
the full form used in contracts and policy documents
- errors and omissions insurance
common American term for a similar kind of cover
- liability cover
broader and can include other kinds of protection
文法句型
buy PI
renew PI
PI insurance
用法筆記
Usually written as PI or PI insurance in business documents. Object is normally a policy bought by people who give paid professional advice or design work.
常見錯誤
7. a short way of writing personal injury, harm to a person's body or mind, especia
人身傷害
因他人過失造成的身心傷害
a short way of writing personal injury, harm to a person's body or mind, especially in a legal case against someone else.
The lawyer moved Nina's PI case to the county court.
那名律師把 Nina 的人身傷害案件移到郡法院。
PI case
On the claim form, PI covers both pain and lost wages.
在求償表上，PI 包含疼痛賠償和薪資損失。
PI claim
After the crash, the insurer opened a PI file for Jorge.
車禍後，保險公司替 Jorge 開了一份 PI 檔案。
The firm offers PI advice after workplace accidents.
那家公司提供職災後的人身傷害法律諮詢。
- personal injury
the full legal term; PI is the common short form in files and ads
- bodily harm
focuses more on physical damage and less on the legal case
- injury claim
names the request for compensation rather than the harm itself
文法句型
PI case
PI claim
PI file
用法筆記
Often appears before words like case, claim, file, or lawyer in legal English. Distinguish from sense 6: this PI is the injury itself or the related legal matter, not the insurance policy.