Word.ws English Dictionary

lightspeed

lightspeed noun: the speed of light (in vacuum unless another medium is specified).

Noun

lightspeed (countable and uncountable, plural lightspeeds)

  1. The speed of light (in vacuum unless another medium is specified).
    • If we're going to a world a hundred light-years from here at near lightspeed, we spend according to our own perceptions, only a few minutes doing so and arrive only a few minutes older.1994, Ursula K. Le Guin, A Fisherman of the Inland Sea, Victor Gollancz (UK), published 1996, →ISBN, page 7
    • He paused, then finished, “with the drive from the Linz, he can do over 500 lightspeeds to meet us.2005, W. Strawn Douglas, Oracle And Other Stories, page 134
    Synonyms:
    speed of light
  2. (colloquial, figuratively) An extremely fast speed.
    • In recent years, other activist terms have followed light-speed trajectories. The term “Latinx” overtook academic institutions and briefly became fashionable in the media, still prevalent in some influential publications, like The New Yorker, even though only 3 percent of Hispanics (or Latinos, if...2022 October 23, Pamela Paul, “Let’s Say Gay”, in The New York Times
    Synonyms:
    speed of light

lightspeed meaning in Arabic, Persian, Thai and Vietnamese

lightspeed in Arabic

the speed of light
سُرْعَةْ اَلضَّوْء surʕat aḍ-ḍawʔ

lightspeed in Persian

the speed of light
سرعت نور sor'at-e nur

lightspeed in Thai

the speed of light
ความเร็วแสง kwaam-reo-sɛ̌ɛng

lightspeed in Vietnamese

the speed of light
tốc độ ánh sáng

Synonyms of lightspeed

Forms of lightspeed

plurallightspeeds
alternative formlight speed

Origin of lightspeed

From light + speed.

Words formed from lightspeed

Phrases with lightspeed

Questions about lightspeed

What does lightspeed mean?
Lightspeed means the speed of light (in vacuum unless another medium is specified).
What is lightspeed in Arabic?
Lightspeed in Arabic is سُرْعَةْ اَلضَّوْء (surʕat aḍ-ḍawʔ). See Lightspeed meaning in Arabic.
What part of speech is lightspeed?
Lightspeed is a noun.
What is the plural of lightspeed?
The plural of lightspeed is lightspeeds.

Words near lightspeed in the dictionary

  1. lightsome
  2. lightsomely
  3. lightsomeness
  4. lightsource
  5. lightsources
  6. lightspeed
  7. lightspeed lag
  8. lightspeed lags
  9. lightspeeds
  10. lightstation
  11. lightstations

Source and license

Adapted from Wiktionary: lightspeed (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

Last updated:

Pronunciation audio from Wikimedia Commons, each file under its own free license: en-us-lightspeed.ogg.

Cite this entry: “lightspeed.” Word.ws, https://word.ws/lightspeed. Based on Wiktionary, CC BY-SA 4.0.