1. A term that has come to describe GAINAX's often exaggerated animation of female characters' bouncing breasts. The term has its roots in Gunbuster (Top wo Nerae!), GAINAX's first OVA(1988) with an otaku-focused demographic, in which gainax bounce is found unabated in the three female characters of Noriko, Kazumi, and Jung. Utilization of gainax bounce can still be seen in GAINAX's works, partially as self-reference and self-homage and partially for pure fanservice.
2. Fanservice as it pertains to anime produced by GAINAX, primarily focused on female mammaries.
2. The Evangelion Rebuild movies need moar gainax bounce.