speed of light
noun
Simple meaning
The speed at which light travels in a vacuum.
Pronunciation
Say it like this:
speeduhvlytSay the bold part a little louder.
IPA pronunciation (US)
ˈspiˈdʌvˈlaɪt
This word is pronounced essentially the same in American and British English, so one transcription covers both.
IPA (International Phonetic Alphabet) is a standard way of writing speech sounds.
Definition
Everyday modern meanings first, grouped by part of speech.
noun
physics
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
cellular automata
A rate of travel of a signal equal to one cell per generation, the fastest possible speed in the Moore and von Neumann neighborhoods.
colloquialfigurative
A very rapid speed.
physics
The speed of electromagnetic radiation, which in a perfect vacuum is equivalent to 299,792,458 metres per second.
Word Aura™
How this word commonly comes across.
This meaning: 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
Used this way, speed of light is a specialist word that usually carries little praise or criticism of its own. This is a scientific use: it names something precisely within a field of study, so it appears in research and teaching more than in conversation.
- Emotional tone
- Neutral
- Formality
- Specialist/technical
- Intensity
- Not strongly marked
- How common
- Specialized
- Connotation
- Clinical and technical
- Usage feel
- Technical and specialized
Where it naturally appears
- Science
- Academic writing
- Technical/specialist writing
Usage note
In general conversation this sense usually needs explaining — outside its field, people reach for a plainer word.
Word Aura describes common impressions, not a measurement. Tone changes with sentence, speaker, relationship and situation.
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Dictionary data from Wiktionary via the Free Dictionary API. Simple meanings, combinations and word intelligence are built from verified reference data, no AI is used to load this page.