The definition of locomotion is motion or the ability to move from one place to another.
When a train goes from a station in New York to a station in Pennsylvania, this is an example of locomotion.
locomotion definition by Webster's New World
motion, or the power of moving, from one place to another
Origin: loco- plush motion Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc. locomotion definition by American Heritage Dictionary
noun The act of moving from place to place. The ability to move from place to place. Origin: Latin locō, from a place, ablative of locus, place + motion. The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved. locomotion - Science Definition
The movement of an organism from one place to another, often by the action of appendages such as flagella, limbs, or wings. In some animals, such as fish, locomotion results from a wavelike series of muscle contractions.