Neuter means to remove an animal's reproductive organs so it cannot have babies. When veterinarians neuter a dog or cat, they perform a surgery that prevents the animal from breeding. Pet owners often choose to have their pets neutered to help control the pet population and reduce the number of homeless animals in shelters.

The surgery is different for male and female animals (for females, it's often called spaying), but both procedures can be referred to as neutering. Many veterinarians recommend neutering for pets because it can help them live healthier lives and may reduce certain behavior problems.

The word can also mean to make something powerless or ineffective. If a new rule neuters a club's ability to choose its own activities, it takes away the members' power to decide for themselves. When people say a law has been neutered, they mean it's been changed so much that it can't accomplish what it was supposed to do. In this sense, neuter means draining something of its strength or removing its ability to have an effect.