1. In baseball, a batter is out from the play if they strike (miss hitting the ball) three times. When was the three-strike rule first implemented in baseball? I don't enforce the three-strikes rule when I'm playing with my kids. I just let them try batting for as long as it holds their interest.
2. Three mistakes, transgressions, or issues will lead someone to failing or being dismissed. We've got a three-strike rule around here, and you've already been late twice this quarter. Three strikes and you're out. The school has a three-strikes rule regarding truancy.
3. In law, if one receives a third felony conviction for a serious or violent crime, they can be sentenced to life in prison. Man, they could put you away for a crime like this under the three-strike rule.
See also: rule
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.