speed of light

speed of light (plural speeds of light) (abbreviated as c)

1. (physics) The speed of electromagnetic radiation; in a perfect vacuum it is defined as 299,792,458 metres per second
   • 2011 September 22, Nick Collins, “Speed of light 'broken' by scientists”, in Daily Telegraph‎:

     The science world was left in shock when workers at the world's largest physics lab announced they had recorded subatomic particles travelling faster than the speed of light – a feat that Einstein said was impossible.

2. (colloquial, figuratively) A very rapid speed.

• Einstein barrier
• Einstein constant
• lightspeed
• light speed
• c

• subluminal
• tardyon
• luxon
• tachyon
• faster-than-c
• faster-than-light (FTL)
• superluminal