The story
By analogy with Christian feast days, with a blend of Tottenham + tottering.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: The day in an English Premier League football season on which it becomes mathematically impossible for Tottenham Hotspur F.C. to finish above Arsenal F.C. in the final rankings. Full definition →
By analogy with Christian feast days, with a blend of Tottenham + tottering.
Etymology from Wiktionary, CC BY-SA 4.0.