It means “The day before the calendrical beginning of spring” in English. It’s the day before “Risshun“.
“Setsu” of the first character means “Season”, and “Bun” of the second character means “Divide”.
On this day, we have some events for drive out evil spirits.
First, we eat “Ehou-maki” (rolled sushi) in silence while praying and facing the yearly lucky compass direction.
Second, we throw the roasted soybeans out the door while shouting “Demons out! Luck in!”.
At last, we eat the roasted soybeans the number of ages to become healthy.
Do you like spring? Please let me know your favorite words about a season.