# lightspeed

> English word · Noun · frequency rank #61,593

## Definitions
1. The speed of light (in vacuum unless another medium is specified).
2. An extremely fast speed.

## Etymology
From light + speed.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/lightspeed