Actual meaning of Shiva ratri unveiled by our beloved guru " Sri Sri Kowta Markandeya Sastry garu" (in English)
Mahasivaraatri : Ordinarily, every month one Sivaratri comes. It is called Maasa Sivaratri. This Maha Sivaratri comes in Amavasya(New Moon), Uttaraayan, maagha maas, Krishnapaksh, after Chaturdasi. As a matterof fact this MahaSivaratri comes at the junction of Krishna Paksha Chaturdasi and Amavasya. As such it is having a speciality. In Uttarayan, the currents travel from South(Mooladhara) to North(Sahasraara). These currents are very prominent. Kriyayoga sadhak gets more and more happiness. The meditating Kriya yoga sadhak who is in darkness i.e., KrishnaPaksha, shall do his sadhana with more intensity and dexterity. Then he shall be able to behold his Third eye that exists in Kootastha, the place between eye brows. This is called Maha Sivaratri. That is why this is Maha=Great, Siva=auspicious, Ratri=Night.