What is the difference between Shivratri and Mahashivratri?

Shivratri is observed every month on the 14th night of the waning moon to honour Lord Shiva. Mahashivratri, celebrated once a year in Phalgun, holds greater spiritual importance. It marks the union of Shiva and Shakti and is associated with Lord Shiva’s divine marriage to Goddess Parvati, involving stricter fasting and night-long worship.