goose
noun [ C ]
uk/ɡuːs/ usthe goose that lays the golden egg(s)
the thing that makes you the most money:
The fuel and energy sector is the goose that lays the golden eggs.
kill the goose that lays the golden egg(s)
to destroy the thing that makes you the most money, or stop it from making money:
Raising entry prices to tourist attractions will kill the goose that lays the golden egg for this town. No-one will come here any more.