Aciu is a Lithuanian word (properly written Ačiū) which means Thank You.
And that's why I named this site Ačiū. Thank You is the most valuable word you can learn in any language when you are travelling.
How to pronounce Ačiū is so simple, you'll never forget it.
Achoo. Yup, that's right, like a sneeze. Now go amaze your friends with your new found knowledge.