Winless season
A winless season is a regular season in which a sports team fails to win any of its games. The antithesis of a perfect season, this ignominy has been suffered eleven times in professional American football, six times in arena football, three times in professional Canadian football, once each in American professional lacrosse and box lacrosse, more than twenty-five times in major Australian football leagues, thirteen times in top-level rugby league, at least twice in top-level rugby union, and twice in English county cricket.
American football
Because of the short schedules of college and professional football seasons, there is a possibility that a very bad team will not manage to win any games. Before overtime was used consistently, teams might tie a game without winning one; these are generally counted in lists of winless seasons. This is because, during eras before overtime was introduced to American football, leagues generally ignored tied games when calculating winning percentage.