Definition of "once"

Orion hit a rabbit once; but though sore wounded it got to the bury, and, struggling in, the arrow caught the side of the hole and was drawn out. Indeed, a nail filed sharp is not of much avail as an arrowhead; you must have it barbed, and that was a little beyond our skill. Ikey the blacksmith had forged us a spearhead after a sketch from a picture of a Greek warrior; and a rake-handle served as a shaft.

1879, R[ichard] J[efferies], chapter II, in The Amateur Poacher, London: Smith, Elder, & Co., […]

The hovel stood in the centre of what had once been a vegetable garden, but was now a patch of rank weeds. Surrounding this, almost like a zareba, was an irregular ring of gorse and brambles, an unclaimed vestige of the original common.

1944, Miles Burton, chapter 5, in The Three Corpse Trick

Now we are liberal with our innermost secrets, spraying them into the public ether with a generosity our forebears could not have imagined. Where we once sent love letters in a sealed envelope, or stuck photographs of our children in a family album, now such private material is despatched to servers and clouds operated by people we don't know and will never meet.

2013 June 14, Jonathan Freedland, “Obama's once hip brand is now tainted”, in The Guardian Weekly, volume 189, number 1, page 18

The wisdom of God thought fit to acquaint David with that court which we shall once govern.

1612–1626, [Joseph Hall], “(please specify the page)”, in [Contemplations vpon the Principall Passages of the Holy Storie], volumes (please specify |volume=II, V, or VI), London

Not only were Jupp Heynckes' team pacey in attack but they were relentless in their pursuit of the ball once they had lost it, and as the game wore on they merely increased their dominance as City wilted in the Allianz Arena.

2011 September 27, Alistair Magowan, “Bayern Munich 2 - 0 Man City”, in BBC Sport‎

In his submission to the UN, [Christof] Heyns points to the experience of drones. Unmanned aerial vehicles were intended initially only for surveillance, and their use for offensive purposes was prohibited, yet once strategists realised their perceived advantages as a means of carrying out targeted killings, all objections were swept out of the way.

2013 June 7, Ed Pilkington, “‘Killer robots’ should be banned in advance, UN told”, in The Guardian Weekly, volume 188, number 26, page 6