n A throng or crowd of people or things; a mass, a pack. (defdate|from 16th c.)
n (context|Australian Rules Football) Contesting a bounce or ball up; used appositionally in "ruck contest". Rucks also used collectively either of ruckmen or of ruckmen and ruck rovers, and occasionally used in place of "followers" (including rovers too). (defdate|from 19th c.)
n (rugby union) The situation formed when a runner is brought to ground and one or more members of each side are engaged above the ball, trying to win possession of it; a loose scrum. (defdate|from 20th c.)
n The common mass (term|of) people or things; the ordinary ranks. (defdate|from 19th c.)
v (obsolete|transitive) To act as a ruckman in a stoppage in Australian Rules football.