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saccade

[sa-kahd, suh-]
noun
  1. the act of checking a horse quickly with a single strong pull of the reins.
  2. Ophthalmology. the series of small, jerky movements of the eyes when changing focus from one point to another.

Origin of saccade

1720–30; < French saccade jerk, jolt, orig., movement of a horseman who abruptly pulls the reins, equivalent to Middle French saqu(er) to pull violently (N dialectal variant of Old French sachier, ultimately derivative of sac sack1, hence presumably with sense “withdraw from a sack”) + -ade -ade1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for saccade

saccade

noun
  1. the movement of the eye when it makes a sudden change of fixation, as in reading
  2. a sudden check given to a horse

Word Origin for saccade

C18: from French: a jerk on the reins of a horse
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
Word Origin and History for saccade
n.

1705, from French saccade "a jerk," from obsolete saquer "to shake, pull," dialectal variant of Old French sachier, ultimately from Latin saccus "sack" (see sack (n.1)). Related: Saccadic.

Online Etymology Dictionary, © 2010 Douglas Harper
saccade in Medicine

saccade

[să-käd′, sə-]
n.
  1. A rapid intermittent eye movement, as that which occurs when the eyes fix on one point after another in the visual field.
Related formssac•cad′ic (-kä′dĭk) adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.