upon one's speed

== English == === Alternative forms === upon the speed at the speed at one's speed on one's speed on the speed === Prepositional phrase === upon one's speed (obsolete) At speed; moving rapidly. 1662, Thomas Salusbury, Galileo's dialogue Concerning the Two Chief World Systems (Dialogue Two) In case any one, riding a horse that was upon his speed, should let a bowl drop out of his hand, that bowl being fallen to the ground would continue its motion and follow the horses steps, without tarrying behind him. === References === John A. Simpson and Edmund S. C. Weiner, editors (1989), “upon one's speed”, in The Oxford English Dictionary, 2nd edition, Oxford: Clarendon Press, →ISBN.