What is the Lua language used in Conky script?

I've been experimenting with Linux on a spare PC using Crunchbang so that I can try changing things and tinker. The Conky system monitor is fun to work with and changes are immediately seen, so it's a great hands-on educational tool. I've read that it uses the Lua language which I've never heard of. Usually, it's python or perl or C++. What is the Lua language and is it worthwhile to learn it for beginners to programming?