1. To change, transform, make different, amend, modify, or vary: The blonde wig completely altered Laura's appearance and she said that she would also alter her dress.

When the woman lost weight, she had all of her clothes altered to fit her new figure.

2. To spay or to perform a medical operation on an animal; such as, a cat or a dog: Ted's dog was taken to the vet to be altered so she couldn't have any puppies.

1. An adjustment of a garment so it will fit better.
2. A spaying or the sterilization of an animal; such as, a cat or a dog: Tom's two cats had an altering so they could not have kittens because it would be too difficult to find homes for them.
3. Something that has been changed by making it different; a transformation of someone or something.