rapidity

Etymology
, from, from.

Noun

 * 1) speed, swiftness; the condition of being rapid
 * 2)  A measure of velocity relative to the speed of light
 * 3)  A measure of the velocity of a particle in a beam relative to the beam's axis
 * 1)  A measure of the velocity of a particle in a beam relative to the beam's axis

Translations

 * Bulgarian:
 * Esperanto: rapideco
 * French: ,
 * Greek:
 * Ido:
 * Italian:
 * Polish:
 * Romanian:
 * Spanish: ,
 * Swedish:, ,
 * Tagalog: bilis,
 * Volapük: