Definition of "crit"

Now when talking randomness, players don't mind as long as it's not a negative random chance, for instance, missing causes more annoyance than an opponent dodging, we don't mind an opponent critting against us, but we hate it if something we do affects how much damage we take (aka rolling a 1).

2010 Christopher Wragg, replying to Timothy Ryan's MMO Balancing Techniques Gamasutra

Finally, the Axtinguisher just about edges the Neon Annihilator as the best melee weapon because you're in control of whether your target's on fire or not, whereas the Neon Annihilator's critting of wet targets is down to your team.

January 2013 Elliot Metson, Team Fortress 2 guide - conquering Mann vs Machine's expert mode PC Gamer

It's easy to look past his low health when he's critting for triple damage on more than half his hits.

August 2013 Nic rowen, Rogue Legacy: Family survival guide Destructoid

Chiefly, I suspect, it's because we want to try out the Soldier's new parachute. Although, I'm just as interested in the Scout's new back-critting shotgun.

2014, Phil Savage, Team Fortress 2's 'Love and War' update out now, PC Gamer

Boundless Strike looks like Fissure only without the giant wall of earth, instead critting and stunning enemies in a line.

2016 Dota 2 7.00 patch adds Monkey King, talents, new HUD, more PC Invasion

Fixed a bug where, when Statikk Shiv’s chain lighting was proc’d by Pulsefire Ezreal’s Q - Mystic Shot, it wasn’t properly critting at 100% crit chance

2017, League of Legends Patch 7.11 change list, The Rift Herald