To save this word, you'll need to log in.
Definition of double helix
: a helix or spiral consisting of two strands in the surface of a cylinder that coil around its axis especially : the structural arrangement of DNA in space that consists of paired polynucleotide strands stabilized by cross-links between purine and pyrimidine bases — compare alpha-helix, watson-crick model
Keep scrolling for more
Keep scrolling for more
Keep scrolling for more
Test Your Vocabulary
Semantic Drift Quiz
- Which of the following was once a synonym for fun?

Can you spell these 10 commonly misspelled words?
TAKE THE QUIZ
Test Your Knowledge - and learn some interesting things along the way.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridgedWords at Play
Ask the Editors
Word Games
Share double helix
Time Traveler for double helix
The first known use of double helix was in 1954
See more words from the same year