Since "one shotting" is generally misused by everyone, always, and "one rotation" generally being the most common way champs get 100-0'd.
"Rengar just came out of stealth and one shot me" - Random player
No, he just used a full rotation to 100-0 you.
One shot is when Ziggs launches just his ult and it 100-0's you, or Syndra presses R and hits you with every ball to 100-0 you.
"One rot" is more accurate in 99% of cases than "one shot".