A goose is a large bird that has a long neck and webbed feet. Geese are often farmed for their meat.

Goose is the meat from a goose that has been cooked.

If you cook someone's goose, you prevent their plans from succeeding.

If someone kills the goose that lays the golden egg, they harm or destroy the person or thing that gives them their money, power, or advantage.

If you say what's sauce for the goose is sauce for the gander, you mean what is acceptable for one person in a particular situation should be acceptable for another person in a similar situation.