onside kick

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A kickoff in which the ball carries just far enough, at least ten yards, to be recovered legally by the kicking team.

from the GNU version of the Collaborative International Dictionary of English.

• (Football) A kickoff in which the kicking team attempts to kick the ball only so far as is legally required (beyond the 50-yard line), so as to have a better chance to recover the kicked ball itself; -- it is a risky type of play used only when the kicking team is losing and there is little time left to play.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Alternative spelling of on-side kick.