antiparallel

adjective

an·​ti·​par·​al·​lel
ˌan-tē-ˈper-ə-ˌlel,
ˌan-ˌtī- How to pronounce antiparallel (audio)
-ləl
: parallel but oppositely directed or oriented
antiparallel electron spins
two antiparallel chains of nucleotides comprise DNA

Examples of antiparallel in a Sentence

Recent Examples on the Web
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When in the presence of a magnetic field the spin of the electrons moves either into a parallel or antiparallel position in relation to the field. IEEE Spectrum, 11 May 2013

Word History

First Known Use

circa 1660, in the meaning defined above

Time Traveler
The first known use of antiparallel was circa 1660

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Cite this Entry

“Antiparallel.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/antiparallel. Accessed 29 Oct. 2025.

Medical Definition

antiparallel

adjective
an·​ti·​par·​al·​lel ˌant-i-ˈpar-ə-ˌlel, ˌan-ˌtī-, -ləl How to pronounce antiparallel (audio)
: parallel but oppositely directed or oriented
two antiparallel chains of nucleotides comprise DNA
Last Updated: - Updated example sentences
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