The Turkish knot is symmetrical and the Persian knot is asymmetrical, as shown in this diagram.
The two types of knots most commonly used to make hand knotted oriental rugs are the so-called Persian knot and Turkish knot.
On the loom, long warp strands (often cotton) run vertically from top to bottom. Onto this base the weaver ties pieces of spun, dyed wool in horizontal rows across the loom. Warp-like strands called wefts are woven horizontally across the warp between rows of knots.
The Turkish knot is a symmetrical knot sometimes referred to as the Ghiordes or Gordes knot. The Persian knot is an asymmetrical knot that also goes by the name Senneh knot.
What’s especially confusing is that some Turkish rugs are woven with the Persian knot, and vice-versa. It might be easier to remember the two knots as symmetrical and asymmetrical, and these terms are increasingly used in the oriental rug world.