Oracle ERP is an integrated system managing all aspects of large companies: finance (GL, AP, AR), supply chain (procurement, inventory, manufacturing), HR, and projects. Oracle ERP exists in two forms: Oracle E-Business Suite (legacy, on-premises, dying) and Oracle Cloud ERP (modern, SaaS). Most new implementations use Oracle Cloud. Oracle is enterprise-grade: companies with 10,000+ employees, global operations, complex tax/regulatory needs. A single Oracle ERP instance might handle $10B+ in annual transactions. Implementations are massive: 50+ people, $2-20M budget, 6-36 months timeline.