LFE, or "Lisp Flavoured Erlang", is a Lisp-2 (thus similar to Common Lisp, and MACLISP before that) that runs on top of the Erlang VM or "BEAM". It is the oldest sibling of the many BEAM languages that have been released since its inception (e.g., Elixir, Joxa, Luerl, Erlog, Haskerl, Clojerl, Hamler, etc.).
As a Lisp-2, LFE has different namespaces for functions and variables. Furthermore, LFE has Erlang's notion of arity, so functions with different arity may share the same name.
Lisps are great, but the thing that makes LFE so incredible is that it runs on the Erlang VM and is 100% compatible with Core Erlang.