A tendril is, as a defined by Webster Dictionary, “slender threadlike appendage of a climbing plant, often growing in a spiral form, that stretches out and twines around any suitable support. ”
Pictured here is exactly that. Although, I am unsure of the name of this plant, it is clear to see it is growing and winding around this archway. Also you can see the spiraling tendrils.
Tendrils are specialized stems with a thin and flexible shape that is used by climbing plants for support, attachment and cellular invasion by parasitic plants, most commonly by twirling around hosts.