plectonemic
/ˌplɛktə(ʊ)ˈniːmɪk/Chiefly Molecular Biol.
adjective
Of, relating to, or designating a structure formed by two or more similar helices coiled together side by side in such a way that they cannot be fully separated without being unwound.
Origin
1940s. From ancient Greek πλεκτός twisted + νῆμα thread + -ic.