n :  a region in single-stranded RNA or DNA that is double-stranded due to pairing between purine and pyrimidine bases in adjacent sequences of the RNA or DNA that are complementary and inverted - called also hairpin loop  .
 
   
 
Similar sounding terms:  har·poon 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2025.