DEFI is the acronym for Decentralized Finance.
DEFI/Decentralized Finance is a term used to address the nascent industry of finance that is built by leveraging open-source software and is not dependent on/ connected to, traditional financial environments. DEFI includes products such as exchanges, insurance, loans, and so on.
The term is commonly used interchangeably with the term OPFI (Open-Finance). This is not an accurate linguistic play due to there being a subtle difference between the two; DEFI is rooted in cipher-punk “nobody owns the product” philosophy, empowering the end-user with sovereignty – OPFI philosophy is closer to that of Linux where private companies can offer services built from the open-source software.