Okay, so imagine a guitar but smaller. This is called a mandore. Like a guitar, it has strings that you pluck to make music.
The mandore has existed for a long time, dating back to the 16th century in medieval Europe. It was used a lot in classical music and was popular in France.
Nowadays, you don't see too many people playing the mandore, but some musicians still enjoy it because it has a unique sound.
So basically, a mandore is a small guitar-like instrument with strings that makes music.