Incorporation is making something part of a whole. The incorporation of egg yolks into a hot liquid must be done slowly so the eggs don't curdle.
Incorporation can also refer to making a company a legal corporation, and the "Inc." after many company names stands for "Incorporated." If you're starting a new business, you should look into the laws regarding incorporation in your state, to see if incorporating would make sense for you. When territory is acquired and taken into a larger body, that's also incorporation. The incorporation of your small neighborhood park into the county parks system will help preserve it as a green space.