Word · Frequency #22623
caffeine
咖啡因；咖啡碱
a bitter alkaloid found in coffee and tea that is responsible for their stimulating effects
- 1.
An alkaloid, C8H10N4O2, found naturally in tea and coffee plants, which acts as a mild stimulant on the central nervous system.
一种生物碱,C8H10N4O2,天然存在于茶树和咖啡树中,对中枢神经系统有轻度刺激作用。
一种生物碱,C8H10N4O2,天然存在于茶树和咖啡树中,对中枢神经系统有轻度刺激作用。；咖啡因；咖啡碱；[化] 咖啡因; 咖啡碱
In use
Drinking coffee late at night keeps me awake because of the caffeine.
If you are sensitive to caffeine, try switching to decaffeinated tea.
The label says this energy drink contains about eighty milligrams of caffeine per can.
caffeine + be found in + [food/drink]
用于说明咖啡因的来源，常用于科普或日常说明。
Caffeine is found in coffee and tea.
咖啡因存在于咖啡和茶中。
caffeine + be responsible for + [effect]
用于解释因果关系，句型较正式。
Caffeine is responsible for the stimulating effects of these drinks.
咖啡因是这些饮品产生提神作用的原因。
Common mistakes
I need a caffeine to stay awake.I need caffeine to stay awake.
caffeine 是不可数名词，不能直接与不定冠词 a 连用；要表示“一杯含咖啡因的饮品”可说 a caffeinated drink 或 a cup of coffee.
I only drink caffeine coffee in the morning.I only drink caffeinated coffee in the morning.
修饰饮品表示“含咖啡因的”要用形容词 caffeinated，caffeine 是名词，不能直接作定语修饰 coffee；也可说 coffee with caffeine，但最小改动是用 caffeinated.
The caffeine of green tea makes me alert.The caffeine in green tea makes me alert.
表示“某物中的咖啡因”应用介词 in 表包含关系，of 表示所属关系在此不自然；这是中文“的”字结构的直译导致的问题.
Connections
Collocations
- caffeine content
- 咖啡因含量
- The label lists the caffeine content of the drink.标签上列出了这种饮料的咖啡因含量。
- caffeine intake
- 咖啡因摄入量
- Doctors recommend limiting your caffeine intake in the afternoon.医生建议你在下午限制咖啡因的摄入。
- caffeine withdrawal
- 咖啡因戒断
- Her headache was caused by caffeine withdrawal after she quit coffee.她戒掉咖啡后，头痛是由咖啡因戒断引起的。
- caffeine sensitivity
- 咖啡因敏感性
- His caffeine sensitivity means he cannot drink soda after dinner.他对咖啡因敏感，所以晚饭后不能喝汽水。
- caffeine buzz
- 咖啡因带来的兴奋感
- I need a caffeine buzz to wake up in the morning.我早上需要咖啡因带来的兴奋感来提神。
Learner notes
Memory Tip
读音近似“咖啡因”，咖啡中让人提神的成分就是 caffeine——记住“咖啡因”三个字即可。
Context & Register
语域：neutral 常见场景：everyday conversation、scientific writing、food and drink labels 该词通常为中性用法，日常对话、科普文章和产品说明中都比较常见，无明显的正式或非正式倾向。
Grammar Note
通常作不可数名词；表示不同种类时可用复数形式 caffeines。
Pronunciation & Spelling
Caffeine /ˈkæfiːn/ has no common exact rhyme because its stressed vowel is /æ/ and the following syllable is /fiːn/. Codeine (/ˈkoʊdiːn/) and protein (/ˈproʊtiːn/) share the final /iːn/ sound and a similar -eine/-ein spelling, but their stressed vowel is /oʊ/, so they do not rhyme. Warning: vein (/veɪn/) has the -ein spelling but is pronounced /veɪn/, not /iːn/; ceiling (/ˈsiːlɪŋ/) and receive (/rɪˈsiːv/) show the -ei- spelling pronounced /iː/ but with different endings.
Usage priority
Collins 词频等级为 1，建议结合例句记忆，而不是只背中文释义。
Learn the forms together
页面下方列出了常见词形变化。学习时注意它们在句子中的语法位置。
Dictionary facts from ECDICT, WIKTIONARY.