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antiparallel

American  
[an-tee-par-uh-lel, an-tahy-] / ˌæn tiˈpær əˌlɛl, ˌæn taɪ- /

adjective

Mathematics, Physics.
  1. (of two vectors) pointing in opposite directions.


antiparallel British  
/ ˌæntɪˈpærəˌlɛl /

adjective

  1. physics parallel but pointing in the opposite direction

  2. maths (of vectors) parallel but having opposite directions

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of antiparallel

First recorded in 1650–60; anti- + parallel

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Wilson continued, "If those magnetic moments interact in a way that wants them to point antiparallel to one another, we call that antiferromagnetism."

From Science Daily Mar. 16, 2026

The two strands run antiparallel to each other.

From Textbooks Jun. 9, 2022

On rare occasions the spins of the protons and electrons in neutral hydrogen atoms flip from being parallel to antiparallel, emitting a photon at a frequency of 1.4 gigahertz—the so-called 21-centimter radiation.

From Science Magazine Jul. 18, 2019

The two strands of DNA’s double helix run antiparallel, or in opposite directions.

From Textbooks Jan. 1, 2018

Each protomer contributes an intertwined helical pair that bends in a left-handed helical 180° turn over the length of the channel, forming an antiparallel coiled coil in the upper and middle part of the pore.

From Nature Apr. 4, 2014

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