Step 1: Understanding the definition of Purana.
The Puranas are a class of ancient Hindu texts that preserve mythology, cosmology, genealogies, and cultural traditions.
The classical definition of a Purana includes five key features, known as Panchalakshana: creation (sarga), recreation (pratisarga), genealogies (vamsha), reigns of Manus (manvantara), and dynastic histories (vamshanucharita).
Step 2: Identification in Vishnupurana.
Among all Puranas, it is the Vishnupurana that explicitly defines what constitutes a Purana by laying out these characteristics in detail.
Step 3: Exclusion of other Puranas.
- Brahmapurana: While it contains creation stories, it does not give the formal definition of Purana.
- Skandapurana: Focuses on pilgrimages and local traditions, not on defining Purana.
- Markandeyapurana: Known for its Devi Mahatmya, not for defining Purana.
Step 4: Conclusion.
Thus, the Purana that provides the definition of Purana is Vishnupurana.