Hurtbox
The hitbox's counterpart: the zone on a character that receives damage, as opposed to the one that deals it.
Fighting games keep two invisible shapes apart. The hitbox marks what does damage — the fist, the blade, the projectile. The hurtbox marks what can take damage — the torso, the head, the outstretched leg. A hit registers when a hitbox overlaps an opponent's hurtbox, not when the sprites touch.
Keeping them separate is what makes tight spacing possible: a kick whose hitbox reaches further than the character's hurtbox lands without being punishable there. Designers tune the shapes frame by frame, and a whole genre's balance rides on where they sit.