Short Answer: Meruem is a Lisp dialect.
Long Answer: Meruem is a dynamically typed interpreted programming language that supports both functional programming (lambdas, closures, higher-order functions, etc) and meta-programming (Lisp macros and quasiquotes).
The interpreter, written in the Scala programming langugae, runs on the Java Virtual Machine (view the code). The standard library is written in Meruem and can be found here.
Like most (if not all) of the Lisps out there, Meruem has a REPL (Read-Eval-Print-Loop) on which you can easily evaluate expressions and get their results immediately.
You can download the latest releases here: https://github.com/melvic-ybanez/Meruem/releases
You can learn the basics of the Meruem programming language by reading the Introduction to Functional Programming in Meruem.