scrum (n.)

late 15c., "a battle," a sense now obsolete, an alteration of skirmish (n.). Sometimes also scrummage, scrimish (16c.). By 1780 as "a confused contest, a tussle;" the meaning in rugby and U.S. football dates from 1857, originally "a confused, close struggle around the ball between players." The sense of "a practice session in which offensive and defensive squads square off" is by 1916.