Plain-English definitions of the core terms for AZ-900 study. Simplified for learning; Microsoft documentation is authoritative.
| Term | Definition |
|---|---|
| Cloud computing | On-demand IT resources delivered over the internet, pay-as-you-go. |
| IaaS | Infrastructure as a Service — you manage OS and apps. |
| PaaS | Platform as a Service — the platform is managed for you. |
| SaaS | Software as a Service — fully managed software you just use. |
| Public cloud | Resources owned and run by a cloud provider. |
| Private cloud | Cloud resources used by a single organisation. |
| Hybrid cloud | A mix of public and private. |
| Shared responsibility | The split of security duties between provider and customer. |
| Region | A geographic area with Azure data centres. |
| Availability zone | A physically separate location within a region. |
| Resource group | A logical container for related resources. |
| Microsoft Entra ID | Azure’s identity service. |
| RBAC | Role-Based Access Control at a scope. |
| Azure Policy | Rules that enforce configuration and compliance. |
| Resource lock | Prevents accidental change or deletion. |
| SLA | Service Level Agreement — the provider’s uptime commitment. |
| Scalability | Adding capacity to meet demand. |
| Elasticity | Scaling up and down automatically. |
| TCO | Total Cost of Ownership — full cost of running workloads. |
| Tag | A label used to organise and track resources and cost. |