Software as a Service (SaaS) represents a cloud-computing deployment model where applications are hosted centrally by a third-party provider and delivered securely over the internet on a subscription basis. Prime real-world examples include Microsoft 365 (offering cloud-based Word, Excel, and Outlook productivity tools), Salesforce (delivering enterprise customer relationship management solutions), Zoom (providing cloud video conferencing and communication infrastructure), and Google Workspace (enabling collaborative document editing and cloud file storage via web browsers), eliminating local installations and manual server maintenance.