Definition

1. Noun:
   • The speed at which light travels in a vacuum; a fundamental constant of nature: This is the maximum speed at which all conventional matter and information in the universe can travel. It is a cornerstone of modern physics, particularly in Albert Einstein's theory of relativity.

Usage Examples

• Noun:
  • According to Einstein's theory, nothing with mass can reach the speed of light.
  • The speed of light in a vacuum is approximately 299,792 kilometers per second.
  • Astronomers measure vast interstellar distances in light-years, the distance light travels in one year at the speed of light.

Advanced Usage

• "At the speed of light": Used metaphorically to describe something that happens extremely quickly.
  • News of the scandal spread across the internet at the speed of light.
• In physics, it is often denoted by the lowercase letter 'c'.
  • Einstein's famous equation is E=mc², where 'c' represents the speed of light.

Variants and Related Words

• Light-speed (adjective, often hyphenated): Describing something that travels at or near the speed of light.
  • The science fiction novel featured light-speed travel.
• c (symbol): The standard scientific symbol for the speed of light in a vacuum.

Synonyms

• Light velocity: A less common but technically accurate synonym.
• c: The standard scientific notation.

Related Phrases

• Faster-than-light: A theoretical concept describing travel or communication that exceeds the speed of light, often abbreviated as FTL.
• Light-year: An astronomical unit of distance, defined as the distance light travels in one year.

Related Idioms

• At the speed of light: While literal in science, this is also a common idiom meaning "with incredible speed."
  • The company's stock value fell at the speed of light after the report was published.

Noun

1. the speed at which light travels in a vacuum; the constancy and universality of the speed of light is recognized by defining it to be exactly 299,792,458 meters per second