Saccade \sa-KAHD\ , noun;
1. The movement of the eye when it makes a sudden change, as in reading
2. The act of checking a horse quickly with a single strong pull of the reins
According to Etymonline.com:
Dating to the mid-18th century, this word comes from French saccade ("a jerk"), which derives from saquer ("to shake, pull"). Saquer is an obscure word that is a dialectal variation on an Old French word, sachier, which is ultimately from Latin saccus, meaning "sack."
*Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Friday, November 5