Meaning of onside kick

on'side kick'

Pronunciation: [key]
— Football. Football.
  1. a kickoff deliberately kicked a short distance in an attempt by the kicking team to regain possession of the ball by recovering it after it has traveled forward the legally required distance of 10 yards, beyond the 50-yard line.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.