1994, Ursula K. Le Guin, A Fisherman of the Inland Sea, 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.
(countable) A rate of speed.
2005, W. Strawn Douglas, Oracle And Other Stories, He paused, then finished, “with the drive from the Linz, he can do over 500 lightspeeds to meet us.
