an advanced baseball statistic (h-hr)/(ab-k-hr+sf) that is used typically by non-athletic caucasian american nerds to attribute the skill of hitting to a random chance. this term is used mostly in conversation by nerds with other nerds to soothe the pain of rooting for a crappy low payroll baseball team that can't get the big hits to win games. when used by a nerd with a non-nerd, it is used in a condescending manner to exemplify their superior knowledge of crappy players and teams who are supposed to be good but aren't because of BABIP.
sabean: "i knew freddy sanchez was going to be clutch and take it to cliff lee in game 1 of the world series and give us the momentum we needed to finally win a world series championship".
beane: "hahaha, you do realize that it was just a fluctuation in BABIP right? oh wait, i forgot, hahaha...you don't know what that is. let me explain...."