Isosceles Stance
A square shooting stance with both arms equally extended toward the target, forming a triangle with the chest.
Also: triangle stance, modern isosceles
The isosceles is the dominant defensive and competitive handgun stance today. Feet roughly shoulder-width and parallel (or strong foot slightly back), hips and shoulders square to the target, both arms extended and forming a triangle with the chest — hence the colloquial name triangle stance. Modern variants (athletic stance, modern isosceles) push the upper body forward into the recoil rather than upright.