the exact time when an attack or other military action will start
The air force planes waited until zero hour in order to begin their bombing mission.
The last three days of the Navratri festival, i.e. Ashtami, Navami, and Dashami are celebrated as Saraswati Puja. The celebrations start with the Puja Veypu (Offering for Worship). It consists of placing the books for Pooja on the Ashtami day.It may be in one own house, in the local Nursery School run by traditional teachers, or in the local temple. The books will be taken out for reading, after worship, only on the morning of the third day (Vijaya Dashami). It is called Puja Eduppu (Taking back after Puja). Children are happy since they are not expected to study on these days. On the Vijayadashami day, Kerala celebrates Vidyarambham also known as Ezhuthiniruthu or Initiation of Writing where children between two and three years old are formally initiated before they are admitted to nursery schools. The child is made to write for the first time on the rice spread in a plate with the index finger, guided by an elder of the family or by a reputed teacher. The little ones will have to write Hari Shri Ganapataye Namah and recite the same to mark the auspicious entry into the world of education. This is considered a memorable event in the life of a person. Ayudha Puja is also conducted during this period.