What is "khandhaka"

Khandhaka ( Pali) is the second book of the Theravadin Vinaya Pitaka and includes the following two volumes:

• Mahavagga:
  includes accounts of the Buddha's and his great disciples' awakenings, as well as rules for uposatha days and monastic ordination.
• Cullavagga:
  includes accounts of the First and Second Buddhist Councils and the establishment of the community of Buddhist nuns, as well as rules for addressing offenses within the community.