Meaning of FitzGerald contraction

FitzGer'ald contrac"tion

Pronunciation: (fits-jer'uld lôr'ents, -lōr'-), [key]
— Physics. Physics.
  1. the hypothesis that a moving body exhibits a contraction in the direction of motion when its velocity is close to the speed of light. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.