A hollow-point bullet is a type of expanding bullet which expands on impact with a soft target, transferring more or all of the projectile's energy into the target over a shorter distance.

Expanding bullets, also known colloquially as dumdum bullets, are projectiles designed to expand on impact. This causes the bullet to increase in diameter, to combat over-penetration and produce a larger wound, thus dealing more damage to a living target. For this reason, they are used for hunting and by most police departments, but are generally prohibited for use in war. Two typical designs are the hollow-point bullet and the soft-point bullet.