This depends on whether you are referring to ropework, embroidery, or a scarf -
in ropework we have a French sinnet, a French shroud knot, French garland, and French masthead knot, to name only a few of the French knots, each with their own unique look;
in embroidery, it has only one common meaning, a simple "button" made by pulling thread/yarn thru a couple loops to pull tight;
for a scarf, it is simply 2 overhand knots with no unique look.
history of french knot
There is a video to show you how to French knot cross stitch: see the related link below.
des noeuds papillon (something like butterfly-knot because of the shape)
A muscle knot is a very tight ball of muscle that forms in areas like the neck, back, and shoulders. Muscle knots constrict to cause pain in these areas.
Is it painful? Does it move when you touch it? Look up "Carbuncle".
A Branch. A knot is formed in wood where a branch grows, and the larger branch or trunk that its growing from grows larger encasing the origin of the branch.
Like french schools.
This is a symmetric knot called the Atlantic Knot. There are sequential images, or a video, at the related links below.
"Nœud." Not sure how to pronounce that.
Another name for the Hercules knot is the square knot.
I look like is "je ressemble à ..." in French.
Like french schools.