Arc vs Ada: What are the differences?

What is Arc? A dialect of the Lisp programming language developed by Paul Graham and Robert Morris. Arc is designed for exploratory programming: the kind where you decide what to write by writing it. A good medium for exploratory programming is one that makes programs brief and malleable, so that's what we've aimed for. This is a medium for sketching software.

What is Ada? A structured, statically typed, imperative, and object-oriented high-level programming language. It is a structured, statically typed, imperative, and object-oriented high-level programming language, extended from Pascal and other languages. It has built-in language support for design by contract (DbC), extremely strong typing, explicit concurrency, tasks, synchronous message passing, protected objects, and non-determinism. Ada improves code safety and maintainability by using the compiler to find errors in favor of runtime errors.

Arc and Ada belong to "Languages" category of the tech stack.