Perhaps he second most common ornament on the oud! The turn is a crucial skill to learn in order to authentically play Arabic music, especially in maqams like Sikah and Rast.  I show a few different variations on the turn and offer some tips on how to play it using different risha (pick) combinations.  

There are actually some more variations I didn't get into here - this was my first video! I am going to follow up with some common alternatives as well as some other picking options.  

The turn is mostly heard on the notes E half flat, B half flat, A half flat and F half sharp.  In fact it's almost required on those notes if you have time to fit it in! It's also pretty common on E flat, B flat, A flat as well as E, B, and A natural. There are also some similar related ornaments that show up on other notes.