Lua
In plain terms
A tiny, fast, embeddable scripting language.
Going deeper
Lua is lightweight and easy to embed into other programs, making it the go-to scripting layer for games and applications. It's simple but flexible.
Under the hood
Its small footprint and the LuaJIT compiler make it remarkably fast; tables are its single, versatile data structure.
Examples
Game scripting (Roblox, WoW), Redis scripts, Nginx (OpenResty), Neovim config.
Think of it like...
Like a compact universal remote that slips into any device to add programmable control.