What is a DeFi farm income?

Could you elaborate on what exactly a DeFi farm income entails? As someone new to the world of decentralized finance, I'm curious to understand how one can generate income through this method. Is it similar to traditional farming but in the digital realm? Or does it involve investing in specific DeFi protocols and earning rewards or interest? Additionally, what are the risks associated with DeFi farming, and how does one ensure the security of their investments in this space?