caffeine

/'kæfi:in/

Thân thiện

A scientist measures caffeine in a laboratory beaker.

Definition

1. Noun:
   • A bitter alkaloid found in coffee and tea that is responsible for their stimulating effects: Caffeine is a natural chemical compound that acts as a stimulant to the central nervous system, commonly consumed in beverages like coffee, tea, and some sodas.

Usage Examples

• Noun:
  • The coffee contains a high amount of caffeine.
  • She avoids caffeine after 3 PM to help her sleep better at night.
  • Caffeine can improve alertness and concentration for a short period.

Advanced Usage

• "Caffeine content": The amount of caffeine present in a food or beverage.
  • Check the caffeine content on the energy drink label.
• "Caffeine-free": Describing a product that contains no caffeine.
  • I drink caffeine-free herbal tea in the evening.

Variants and Related Words

• Caffeinated (adj): Containing caffeine.
  • Most caffeinated drinks provide a temporary energy boost.
• Decaffeinated (adj/adj. used as noun: "decaf"): Having had most or all of the caffeine removed.
  • He ordered a decaffeinated coffee.

Synonyms

• Stimulant: A substance that raises levels of physiological or nervous activity in the body.
• Theine: An older term for caffeine when found in tea.

Related Phrases

• "Caffeine kick" (informal idiom): The sudden increase in energy or alertness felt after consuming caffeine.
  • I need my morning coffee for that caffeine kick to start the day.
• "Caffeine crash" (informal idiom): The feeling of fatigue that can follow after the stimulating effects of caffeine wear off.
  • After the caffeine crash, he felt very tired.

Học thuật

Noun

1. a bitter alkaloid found in coffee and tea that is responsible for their stimulating effects

Từ đồng nghĩa

• caffein