To declare a person no longer belongs to the church

A schism is a formal division in or separation from a church or religious body. *The Great Schism, also known as the East=West Schism, refers to the break between the Roman Catholic Church and the Eastern Orthodox Church.

Explanation:

it's a secular holiday. it is and was a custom developed to recognize the ending of a time and a wish for a good future. the kind of kiss you exchange, if you are single, is intended to predict what kind of year you will have in the coming year.

it is saying good bye to the last year with all its ups and downs, and hello to the new year, with all its hopes and dreams.