Definition of Shivarathri:
Shivaratri literally means “the great night of Shiva“, and is celebrated on the night before the new moon of each month. It is considered the darkest night because it arrives before the start of the lunar cycle towards the full moon.
Masik Shivaratri, is the celebration that is celebrated once a month, on the night that is considered darkest and the beginning of the lunar cycle.
Maha Shivaratri, It is a main festival that occurs only once a year. It is a celebration with the same objective as the Masik Shivaratri, and is celebrated in the month of Phalgun. This celebration is very extensive and relevant in the Hindu calendar.