Covered Knot / Onassis Knot
This is a way to hide the knot. It is very similar to the Overhand-knot, but it is suitable for when you want to give more volume to the knot. Since the knot is covered and cannot be seen, you can choose several tying processes up to halfway. It is now one of Ascot-Tie's knots.
 
It is also called the Onassis knot when tied with a Four-in-hand-tie. However, the tying method used by Aristotle Onassis [1906-1975], the model of Onassis knot, was mostly a Plain-knot, and very rarely, there are photographs which seem to be Overhand-knot.