From Longman Dictionary of Contemporary Englishldoce_073_adouble helixˌdouble ˈhelix noun [countable] technical 
CFHBMa shape consisting of two parallel spirals that twist around the same centre, found especially in the structure of DNA
CFHBMa shape consisting of two parallel spirals that twist around the same centre, found especially in the structure of DNAExamples from the Corpus
double helix• Each then acts as a template to which other simpler molecules become attached until each has once more become a double helix.• The entwined serpents forming a double helix gave birth to the Caduceus.• Cobras are constantly depicted entwined in a double helix.• If the ends of such non-dividing clone are held while it grows, then unexpectedly a double helix appears.• Thus each double helix becomes two double helices, with the two new doublets remaining joined at the centromere.• In the formation of the double helix, a total of 12 rotors are restricted per base pair stack.• These conformations influence the position of the phosphate group with respect to the grooves of the double helix. 