noun
five-second rule (food hygiene myth)
Refers to the popular belief that food dropped on the floor is safe to eat if picked up within five seconds. Often used humorously.
床に落としたクッキーを拾って、「５秒ルールだから大丈夫」と言った。
I picked up the cookie I dropped on the floor and said, 'It's okay, five-second rule.'
noun
five-second rule (basketball)
In basketball, a rule requiring a player to pass, shoot, or dribble within five seconds when closely guarded, or when inbounding the ball.
バスケットボールの試合で、選手が５秒ルールを破って相手ボールになった。
In the basketball game, the player violated the five-second rule and the other team got the ball.