Oracle Function was announced late last year (2018), with limited availability to select Oracle Cloud customers. The platform is built on Fn and is Oracle's solution for developers wanting to deploy services using a Serverless Framework.
As succinctly explained by Kaslin Fields, a Fn function is a small embodiment of code that listens and speaks to HTTP streams. Ideally, each Fn function serves one, and only one purpose. It can be implemented in wide variety of programming languages and they are listed here (see the list of runtime options available).