cash cow 
noun informal
A business, investment, or product that provides a steady income or profit.With new competitors nibbling at local business, the old cash cow is starting to dry up....
- The ticket inspection regime is aimed at bolstering the finances of a system that serves as a cash cow for private companies, but has nothing to do with providing adequate services for commuters.
- ‘Everyone sees the SME market as the big cash cow that nobody has cracked yet,’ he said.
- Ruppia
- ruptic
- ruption
- ruptive
- rupture
- ruptured duck
- rupturewort
- rupturing capacity
- rural
- rural carrier
- rural dean
- rural delivery
- rural district
- rural district council
- rural economics
- rural economist
- rural economy
- Rurales
- rural free delivery
- rural guard
- rural industry
- Rural Institute
- ruralism
- ruralist
- ruralite