An omnivore is an animal that eats both plants and animals for their main food. Pigs are omnivores, so they would be just as happy eating an apple, or the worm inside the apple.
Omnivore comes from the Latin words omni, meaning "all, everything," and vorare, meaning "to devour." So an omnivore will eat pretty much eat anything in sight. Humans are genetically designed to be omnivores, but some people choose to limit their diets. When a person is described as an omnivore, it usually means he's willing to eat all kinds of foods and is not a vegetarian or a vegan or on some other kind of special diet.